rexresearch.com
Christina LOMASNEY, et
al.
Modumetal Nanolamination
Modumetal Nanolamination
http://www.technologyreview.com/news/534796/nano-manufacturing-makes-steel-10-times-stronger/
February 16, 2015
Nano-Manufacturing Makes Steel 10
Times Stronger
A new way to produce metals could have wide-ranging effects.
by Kevin Bullis
A new way to produce metals could have wide-ranging effects.
by Kevin Bullis
An inexpensive new process can increase the strength of metals such as steel by as much as 10 times, and make them much more resistant to corrosion. If the modified metals pass field testing, the new process could go on to make bridges and other infrastructure last far longer; it could also make cars lighter and therefore more fuel-efficient.
The Seattle-based startup that developed the process, Modumetal, is commercializing it in part with collaboration with the oil companies Chevron, Conoco-Philips, and Hess.
Parts made using the technology are being tested in oil fields now. Some oil contains highly corrosive chemicals such as hydrogen sulfide that quickly damage production equipment. The new technology could make those parts last much longer and thus lower the cost of pursuing unconventional sources of oil. That could be just the first of a wide range of applications.
The advance is based on the fact that controlling the structure of metals at the nanoscale can imbue those materials with new properties. This has been possible for some time, but it’s been difficult to do reliably and economically with large pieces of metal. Modumetal has developed a process that gives it precise control over the structure of metals, and which allows it to make parts that are meters long. CEO Christina Lomasney says the process costs the same as conventional metal treatments such as galvanization.
Modumetal uses an advanced form of electroplating, a process already used to make the chrome plating you might see on the engine and exhaust pipes of a motorcycle. Electroplating involves immersing a metal part in a chemical bath containing various metal ions, and then applying an electrical current to cause those ions to form a metal coating.
The company uses a bath that contains more than one kind of metal ion and controls how ions are deposited by varying the electrical current. By changing the current at precise moments, it can create a layered structure, with each layer being several nanometers thick and of different composition. The final coating can be up to a centimeter thick and can greatly change the properties of the original material.
David Lashmore, a professor of materials science at the University of New Hampshire who has conducted work in the area, says nano-engineered layers can make a material stronger by stopping cracks from moving through it.
Lashmore says making the process work at a large scale requires a detailed understanding of the physics and chemistry involved to produce exactly the right alloys. Modumetal’s work is “really impressive,” he says.
Modumetal is ramping up its production capacity at its factory in Snohomish County, Washington. The company’s cost claims have yet to be proved in large-scale production, and before the materials can be widely used, standards bodies will need to develop tests to ensure their performance.
Modumetal
Modumetal is a revolutionary nanolaminated alloy that is stronger and lighter than steel and will replace conventional metals and composites in many applications, starting with military armor, and eventually in cars, planes, buildings, and other transportation and construction sectors...
Modumetal is:
A unique, nanolaminated material with ultra high strength to weight properties
A material that negates conventional tradeoffs in metal and composite performance properties
A low-cost, high-efficiency, “green” metal manufacturing process
A single-step, net shape part manufacturing process
Technology
Modumetal is creating a revolutionary new class of nanolaminated materials that will change design and manufacturing forever by dramatically improving the structural, corrosion and high temperature performance of coatings, bulk materials and parts
Modumetal is based on the interaction of different materials at their interfaces. By laminating metals, Modumetal creates a new way to influence material properties. By growing metal using low-cost electrochemistry, Modumetal enables a whole new class of applications of these materials...
Modumetal Patents
FUNCTIONALLY GRADED COATINGS AND CLADDINGS FOR CORROSION AND HIGH TEMPERATURE PROTECTION
US2012234681
FUNCTIONALLY GRADED COATINGS AND CLADDINGS FOR CORROSION AND HIGH TEMPERATURE PROTECTION
US2012234681
The present disclosure describes functionally graded coatings and claddings for corrosion and high temperature protection
[0001] This application claims the benefit of U.S. Provisional Application No. 61/186,057, filed Jun. 11, 2009, tilted Functionally Graded Coatings and Claddings for Corrosion and High Temperature Protection, incorporates herein by reference in its entirety.
[0002] A process for depositing functionally graded materials and structures is described for manufacturing materials that possess the high temperature and corrosion resistant performance of ceramics and glasses, while at the same time eliminating the common mismatches encountered when these are applied to structural metal or composite substrates. An example of the structure of a functionally graded coating is shown in FIG. 1. An example of the functionally graded coating structure applied to a pipe is shown in FIG. 2.
[0003] Electrolytic deposition describes the deposition of metal coatings onto metal or other conductive substrates and can be used to deposit metal and ceramic materials via electrolytic and electrophoretic methods. Electrodeposition which is a low-cost method for forming a dense coating on any conductive substrate and which can be used to deposit organic primer (i.e. “E-coat” technology) and ceramic coatings.
[0004] The embodiments described herein include methods and materials utilized in manufacturing functionally graded coatings or claddings for at least one of corrosion, tribological and high temperature protection of an underlying substrate. The technology described herein also is directed to articles which include a wear resistant, corrosion resistant and/or high temperature resistant coating including a functionally-graded matrix.
[0005] One embodiment provides a method which will allow for the controlled growth of a functionally-graded matrix of metal and polymer or metal and ceramic on the surface of a substrate, which can corrode, or otherwise degrade, such as a metal.
[0006] Another embodiment provides a method which includes the electrophoretic deposition of controlled ratios of ceramic pre-polymer and atomic-scale expansion agents to form a ceramic (following pyrolysis). This form of electrophoretic deposition may then be coupled with electrolytic deposition to form a hybrid structure that is functionally graded and changes in concentration from metal (electrolytically deposited) to ceramic, polymer or glass (electrophoretically deposited).
[0007] Embodiments of the methods described here provide a high-density, corrosion and/or heat resistant material (e.g., ceramic, glass, polymer) that is deposited onto the surface of a substrate to form a functionally-graded polymer:metal, ceramic:metal, or glass:metal coating. The result is a coating, of controlled density, composition, hardness, thermal conductivity, wear resistance and/or corrosion resistance, that has been grown directly onto a surface.
[0008] The functionally-graded coating made according to the methods disclosed hereinmay be resistant to spallation due to mismatch in any of: coefficient of thermal expansion, hardness, ductility, toughness, elasticity or other property (together “Interface Property”), between the substrate and the ceramic, polymer, pre-ceramic polymer (with or without fillers) or glass (together “Inert Phase”) as the coating incorporates a material at the substrate interface, which more closely matches the Interface Property of the substrate.
[0009] In general, coatings made according to methods described herein are resistant to wear, corrosion and/or heat due to the hard, abrasion-resistant, non-reactive and/or heat-stable nature of the Inert Phase.
[0010] Polymer-derived ceramics that incorporate active fillers (e.g., TiN, Ti disilicide, and others) to improve density, have shown promise as a way to process a variety of Inert Phases, which are more dense than polymer-derived ceramics which do not incorporate these fillers. Polymer-derived ceramic composites have been demonstrated for applications, including-oxidation resistance and thermal barriers, due to their high density and low open-pore volume (e.g., the ceramic has less than 1, 5, 10, 20, 30, 40, or 50 percent voids based on volume). See, J D Torrey and R K Bordia, Journal of European Ceramic Society 28 (2008) 253-257. These polymer-derived ceramics can be electrophoretically deposited. Electrophoretic deposition is a two-step process. In a first step, particles suspended in a liquid are forced to move towards one of the electrodes by applying an electric field to the suspension (electrophoresis). In a second step (deposition), the particles collect at one of the electrodes and form a coherent deposit on it. Since the local composition of the deposit is directly related to the concentration and composition of the suspension at the moment of deposition, the electrophoretic process allows continuous processing of functionally graded materials. Polymer-derived ceramics is the method used in commercial production of Nicalon® and Tyranno fibers.
[0011] In embodiments, the technology of this disclosure includes the use of electrochemical deposition processes to produce composition-controlled functionally-graded coating through chemical and electrochemical control of the initial suspension. This deposition process is referred to as Layered Electrophoretic and Faradaic Depostion (LEAF). By controlling the composition and current evolution during the deposition process, LEAF affords the means to engineer step-graded and continuously graded compositions; see Figs. and reference graphs that show dependence of Ni and Si as a function of solution chemistry and current density. Control of current evolution and direction of the electric field also offers the possibility to orient anisotropic powders allowing intimate control of both the density AND the morphology of the Inert Phase (e.g., the content and organization of added ceramic, polymer or glass materials incorporated into an electrodeposited functionally-graded coating). For example, in one embodiment by controlling current evolution and the direction of the electric field in a solution including pre-ceramic polymer, the resulting density of ceramic can be varied through the coatings to produce a varying morphology of ceramic/metal composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1. is an illustration of a functionally graded material.
[0013] FIG. 2. is an illustration of a pipe based on functionally graded material shown in FIG. 1.
[0014] FIG. 3. is graph illustrating mass loss of a substrate per area over time for several materials exposed to concentrated sulfuric acid at 200 degrees C.
[0015] FIG. 4 illustrates Active Filler Controlled Pyrolysis.
[0016] FIG. 5. illustrates LEAF electrophoretic deposition process on a fiber mat.
[0017] FIG. 6 illustrates the concentration of Si and nickel in deposits found by changing the current density. Si is the left most member of each bar graph pair and nickel the right most member of each bar graph pair measured at a specific current density
[0018] FIG. 7 illustrates the concentration of Ni in the emulsion increases from left to right. Si is the left most member of each bar graph pair and nickel the right most member of each bar graph pair prepared with the noted solution concentration of nickel.
DETAILED DESCRIPTION
[0019] Polymer-derived ceramics have shown promise as a novel way to process low-dimensional ceramics, including matrices, fibers and coatings. Polymer-derived ceramic composites have been demonstrated for applications including oxidation barriers, due to their high density and low open-pore volume. See, Torrey and R K Bordia, Journal of European Ceramic Society 28 (2008) 253-257.
[0020] The Active Filler Controlled Pyrolysis (AFCoP), polymer-derived ceramics offer many benefits over tradition ceramic processing methods including:
Liquid form with low crosslinking temperature
High purity reactants
Tailorable composition, microstructure, nanostructures and properties
Ability to produce crystalline and beta-SiC phases
[0025] Pure polymer-derived ceramics suffer from certain performance limitations.
[0026] One such limitation is the occurrence of volume shrinkage—up to 50%, upon sintering. To prevent this, and in order to increase the density of PDC matrices, the AFCoP process is employed, as shown in FIG. 4.
[0027] To produce fully-dense ceramic matrices, the active-filler additive can be occluded into the liquid polymer prior to casting and sintering. During sintering, this additive acts as an expansion agent, resulting in a fully dense part with near zero volume loss (e.g., there are no voids present). Active fillers include Si, Al, Ti and other metals, which on pyrolysis form SiC, Al2O3 or TiSi2, for example. One of the limitations of this process, as it is practiced currently, is the limited reactivity of the fillers. In many cases, due to kinetic limitations, even for the finest available powders, the filler conversion is incomplete. As will be shown in the processes described herein, the reactive “filler” and the polymer will mixed at molecular scale leading to highly efficient conversion of the filler to the product phase.
[0028] Polymer-derived ceramics and in particular, AFCoP ceramics, have shown promise as a novel way to process a variety of ceramics forms, including matrices, fibers and coatings. Polymer-derived ceramic composites have been demonstrated for applications, including-oxidation resistance and thermal barriers, due to their high density and low open-pore volume. See, J D Torrey and R K Bordia, Journal of European Ceramic Society 28 (2008) 253-257. In the some embodiments of this disclosure the AFCoP concept and the LEAF deposition process are combined to enable a manufacturing capability which can produce tailorable, low-cost, ultra-high-performance SiCf/SiC composites and parts.
[0029] The Layered Electrophoretic And Faradaic (LEAF) production process employed herein enables the low-cost production of tailored ceramic matrices. A schematic of one embodiment of that process described in Scheme A.
[0000]
<img class="EMIRef" id="092746074-emi-c00001" />
[0030] Starting from SiC powders and fiber, a first portion of the LEAF process consists in depositing either direct SiC powders, pre-ceramic polymer emulsions (including active fillers) or a combination of these onto the SiC fiber. Electrophoretic deposition is a two-step process. In a first step, particles suspended in a liquid are forced to move towards one of the electrodes by applying an electric field to the suspension (electrophoresis). In a second step (deposition), the particles collect at one of the electrodes and form a coherent deposit on it. Since the local composition of the deposit is directly related to the concentration and composition of the suspension at the moment of deposition, the electrophoretic process allows continuous continuous processing of functionally graded materials.
[0031] A variety of substrates may be employed to prepare the compositions described herein. In one embodiment, the compositions are prepared by the LEAF electrophoretic deposition process outlined above on fiber mat as illustrated in FIG. 5.
[0032] The LEAF process offers the ability to reliably produce composition-controlled “green” (not yet sintered) ceramic through chemical and electrochemical control of the initial suspension. By shaping the starting fiber, which serves as a mandrel, LEAF provides a means to manufacture free standing parts of complex geometry, and hybrid, strength-tailored materials.
[0033] By controlling the composition and current evolution during deposition process, LEAF affords the means to engineer step-graded and continuously graded compositions. Control of current evolution and direction of the electric field also offers the possibility to orient anisotropic powders allowing intimate control of both the density AND the morphology of the ceramic deposit.
[0034] Layer thickness can be controlled by, among other things, the application of current in the electrodeposition process. In some embodiments current density may be varied within the range between 0.5 and 2000 mA/cm<2>. Other ranges for current densities are also possible, for example, a current density may be varied within the range between: about 1 and 20 mA/cm<2>; about 5 and 50 mA/cm<2>; about 30 and 70 mA/cm<2>; 0.5 and 500 mA/cm<2>; 100 and 2000 mA/cm<2>; greater than about 500 mA/cm<2>; and about 15 and 40 mA/cm<2 >base on the surface area of the substrate or mandrel to be coated. In some embodiments the frequency of the wave forms may be from about 0.01 Hz to about 50 Hz. In other embodiments the frequency can be from: about 0.5 to about 10 Hz; 0.02 to about 1 Hz or from about 2 to 20 Hz; or from about 1 to about 5 Hz.
[0035] In some embodiments the electrical potential employed to prepare the coatings is in the range of 5V and 5000 V. In other embodiments the electrical potential is within a range selected from 5 and 200 V; about 50 and 500 V; about 100 and 1000 V; 250 and 2500 V; 500 and 3000 V; 1,000 and 4,000 V; and 2000 and 5000 V.
[0036] In addition to direct electrophoretic deposition of SiC pre-polymers onto SiC fibers, studies have also demonstrated the co-deposition of densification additives. This is similar to the AFCoP process described above. These active-filler additives allow low-temperature densification without any detrimental effects on the fibers, as many densification additives can be sintered well below the re-crystallization temperature of the SiCf. See, A. R. Boccaccini et al., Journal of European Ceramic Society 17 (1997) 1545-1550. By combining these additives into the LEAF process, it is possible to produce high density and density graded ceramic matrices.
[0037] Density gradation allows for the design and development of a highly optimized SiC-fiber:SiC-matrix interface. Density gradation provides a means for balancing the optimization of the interface strength, while still maintaining a high density, and in some embodiments gas impermeable and hermetically sealed matrix. Gas impermeability is especially important in corrosion protection where a high level of gas diffusion through the coating may result in substrate attack. The LEAF process enables control and gradation of density such that a high density region near the substrate may protect the substrate from attack while a low density region near the surface may reduce the thermal conductivity of the coating.
[0038] It is believed to be possible to join non oxide ceramics using preceramic polymers with active fillers based on the work of Borida. See, J D Torrey and R K Bordia, Journal of European Ceramic Society 28 (2008) 253-257. In regard t the embodiments described herein, refinement of the microstructure of ceramics joined by the LEAF processes leads to higher bond strengths In one embodiment of the technology, a sample composition can be controlled by controlling the voltage. Specifically, by slowly transitioning from a low voltage electrolytic deposition regime to a high voltage electrophoretic deposition regime it may be possible to create a functionally-graded material that gradually changes from metal to ceramic or polymer. The same could be achieved by controlling the current to selectively deposit ionic (metal) species and/or charged particle (Inert Phase) species. To create a metal:ceramic functionally graded SiC composite material would significantly increase the corrosion-resistance, wear-resistance, toughness, durability and temperature stability of a ceramic-coated structure.
[0039] In another embodiment, the coating composition can be functionally-graded by modifying the metal concentration in the electrolyte solution during electrochemical deposition. This approach affords an additional means to control the composition of the functionally-graded coating, and allows for deposition to occur at relatively lower current densities and voltages, which produced a better quality in the deposited composites. The standard cathodic emulsion system, where the emulsion particles comprise polymer, pre-ceramic polymer, ceramic or a combination thereof, can be adjusted by adding increasing amounts of nickel to the solution. This embodiment is described in Example #3.
[0040] In other embodiments, this disclosure provides a corrosion resistant coating, which changes in composition throughout its depth, from a high metal concentration at the interface with the substrate to which it is applied to an Inert Phase at the surface.
[0041] In another embodiment, the present disclosure provides a heat resistant coating, which changes in composition throughout its depth, from a high metal concentration at the interface with the substrate to which it is applied to an Inert Phase at the surface.
[0042] As used herein “Inert Phase” means any polymer, ceramic, pre-ceramic polymer (with or without fillers) or glass, which can be electrophoretically deposited. This Inert Phase may include Al2O3, SiO2, TiN, BN, Fe2O3, MgO, and TiO2, SiC, TiO, TiN, silane polymers, polyhydriromethylsilazane and others.
[0043] In some embodiments, ceramic particles may include of one or more metal oxides that can be selected from ZrxOx, YtOx, AlxOx, SiOx, FeOxOx, TiOx, MgO where x=1-4, and include mixed metal oxides with the structure MxY, where M is a metal and Y is ZrxOx, YtOx, AlxOx, SiOx, FexOx, TiOx, MgO. In another embodiment, M is selected from Li, Sr, La, W, Ta, Hf, Cr, Ca, Na, Al, Ti, Zr, Cs, Ru, and Pb.
[0044] As used herein, “metal” means any metal, metal alloy or other composite containing a metal. These metals may comprise one or more of Ni, Zn, Fe, Cu, Au, Ag, Pd, Sn, Mn, Co, Pb, Al, Ti, Mg and Cr. In embodiments where metals are deposited, the percentage of each metal may independently be selected. Individual metals may be present at about 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98, 99, 99.9, 99.99, 99.999 or 100 percent of the electrodeposited species/composition.
[0045] In other embodiments, the coating can have a coating thickness that varies according to properties of the material that is to be protected by the coating, or according to the environment that the coating is subjected to. In some embodiments, the coating can range from 0.2 and 250 millimeters, and in other embodiments the range can vary from 0.2 to 25 millimeters, 25 to 250 millimeters, or be greater than about 25 millimeter and less than about 250 millimeters. In still other embodiments, the coating thickness can range from 0.5 to 5 millimeters, 1 to 10 millimeters, 5 to 15 millimeters, 10 to 20 millimeters, and 15 to 25 millimeters. In still other embodiments, the overall thickness of the functionally-graded coating can vary greatly as, for example, between 2 micron and 6.5 millimeters or more. In some embodiments the overall thickness of the functionally-graded coating can also be between 2 nanometers and 10,000 nanometers, 4 nanometers and 400 nanometers, 50 nanometers and 500 nanometers, 100 nanometers and 1,000 nanometers, 1 micron to 10 microns, 5 microns to 50 microns, 20 microns to 200 microns, 200 microns to 2 millimeters (mm), 400 microns to 4 mm, 200 microns to 5 mm, 1 mm to 6.5 mm, 5 mm to 12.5 mm, 10 mm to 20 mm, 15 mm to 30 mm.
[0046] The functionally graded coatings described herein are suitable for coating a variety of substrates that are susceptible to wear and corrosion. In one embodiment the substrates are particularly suited for coating substrates made of materials that can corrode and wear such as iron, steel, aluminum, nickel, cobalt, iron, manganese, copper, titanium, alloys thereof, reinforced composites and the like.
[0047] The functionally graded coatings described herein may be employed to protect against numerous types of corrosion, including, but not limited to corrosion caused by oxidation, reduction, stress (stress corrosion), dissolution, dezincification, acid, base, sulfidation and the like.
[0048] The functionally graded coatings described herein may be employed to protect against thermal degradation. In one embodiment, the coatings will have a lower thermal conductivity than the substrates (e.g., metal surfaces) to which they are applied.
[0049] The coatings described herein may be employed to protect against numerous types of corrosion, including, but not limited to corrosion caused by oxidation, reduction, stress (stress corrosion), dissolution, dezincification, acid, base, sulfidation and the like. In one embodiment, the coatings are resistant to the action of strong mineral acid, such as sulfuric, nitric, and hydrochloric acids.
EXAMPLES
Example 1
[0050] Preparation of a functionally graded coating comprising a Inert Phase and a metal formed utilizing a combination of electrolytic (faradaic) and electrophoretic deposition includes the following steps:
[0051] 1. Acquire the desired substrate material and cut it to its appropriate size
[0052] 2. Sand the substrate on a circular sander using three steps to achieve a 600 Grit finish
a. 120 Grit
b. 420 Grit
c. 600 Grit
[0056] 3. Attrition Mill TiSi2 powder for 10 or more hours.
a. Add isopropanol to the TiSi2 powder to aid in grinding
b. The longer the time period the smaller the particle size
c. Rinse with isopropanol
d. Dry at 100 C for 8 hours
[0061] 4. Mix the Pre-ceramic Polymer with the solvent
a. Pre-ceramic Polymer, Polyhydridomethysilazane (PHMS): 5.25 g
b. Add to Solvent, n-Octane: 6.25 mL
c. Add an electrodepositable metal species (e.g. Ni) to the slurry
d. The total Volume ratio of slurry: n-Octane is 3:5
[0066] 5. Mix TiSi2 powder at 30% volume with PHMS from step 4 to create slurry
[0067] 6. Ball mill slurry for 4 hours with 200, 5/32? diameter glass beads
[0068] 7. Dissolve the Ru3(CO)12 catalyst in n-Octane
a. Ru3(CO)12: 2.63 mg
b. n-Octane: 6.25 mL
c. Combine the mixture with the slurry
[0072] 8. Ball mill for the entire slurry from step 7 for 30 minutes
[0073] 9. Dip-coat the slurry onto the prepared substrate
a. Dip substrate into slurry
b. Apply a current to affect electrolytic deposition of the metal content of the coating
c. Increase the current to affect electrophoretic deposition of the ceramic content of the coating
d. Attach the substrate to the Instron head
e. Optionally dip into the substrate into the slurry and remove it at a rate of 50 cm/min
[0079] 10. Cross-link the samples in humid air
a. Hang the dipped substrates in a jar filled 1/5 with water
b. Temperature: 150 C
c. Time: 2 hours
[0083] 11. Pyrolyze the dipped samples with flowing air
a. Hang the samples from a ceramic stand and place them in the oven
b. Ramp rate: 2 C/min
c. Hold temperature: 800 C
d. Hold Time: 2 hours
e. Ramp down: 2 C/min
[0089] 12. Remove the completed sample from the oven.
[0090] The resistance of a TiSi2 filled and an unfilled coating to degradation by 200 degree C. concentrated sulfuric acid is shown in FIG. 3. A standard of Alloy 20 and 316 stainless steel are provide for reference. The filled coating showed the least loss of weight.
Example 2
Toughness Improvements Employing Leaf Processes to Incorporate a Low-Content of Metal Binder Into Composites
[0091] In order to improve toughness, the LEAF processes a low-content of a metal binder (e.g., nickel in this Example) may be incorporated into composites. As shown in FIG. 6, the concentration of nickel in deposits can be controlled by changing the current density employed.
Example 3
A Functionally Graded Coating
[0092] In order to create a functionally-graded coating, a standard nickel plating bath was added to the polymer emulsion in 1% increments by volume up to 10%.
[0093] Samples were subsequently exposed to a DC current for a fixed period. The bath was stirred and agitated at the conclusion of each test in order to ensure proper solution mixing and suspension.
[0094] The observations attained from the optical image of the samples were confirmed by the EDX compositional analysis. The Ni composition of the coating was increasing as the Ni concentration in solution increased. These results once again demonstrate the feasibility of creating a functionally graded ceramic:metal composite material by controlling the concentration of metal and Inert Phases in the electrolyte during the deposition process.
[0095] In addition, the data demonstrated that the silicon content in the deposit remain constant over time. This result is to be expected as a result of the voltage driven nature of electrophoretic deposition, and a constant current density and similar voltages were used for the samples. The nickel emulsion system can be optimized through concentration alteration and current and voltage modulation to create a structural material suitable for corrosion resistant, wear resistant, heat resistant and other applications.
Example 4
[0096] Nickel, a siloxane-based pre-ceramic polymer particles and ceramic SiC particles are added to an organic electrolyte Note that in this case, the polymer is not deposited as an emulsion, but rather directly as a lacquer. A cathode and an anode were connected to a power supply. The substrate was connected to the cathode and inert anodes were connected to the anode. A potential was applied across the anodes and cathode, which potential ramped from a low voltage (around 5-100V) to a high voltage (about 100-1000V). The high voltage was held for a period of time. In an SEM of the resulting structure, where gray masses are the SiC fibers the darker gray areas are a mixed matrix of SiOC and SiC. SiOC is present due to the heat treatment in an environment in which oxygen was present. The white areas are where the nickel was able to infiltrate into the cracks and reinforce the structure of the material.
[0097] The addition of the SiC filler particles into the pre-ceramic polymer led to the densification and, strengthening of the specimen by reducing shrinkage on formation. The sub-micron size of the filler particles facilitated the flow and migration of the matrix around the SiC fibers. The upper-right corner of the image contains a zoomed in view of the interface around a fiber. Any gaps present were filled and strengthened by the nickel metal deposition.
[0098] Fiber break analysis was performed on a selection of samples that contained the functionally graded metal:SiC structure to determine the toughness and fracture characteristics of various SiC bundles. The toughness of the fiber matrix can be determined through the visual inspection of fiber pull-out during fracture. This is observed in SEM images of the fracture surface of a dipped coated ceramic bundle cross-linked at 500° F. for 2 hours.
NANOLAMINATE-REINFORCED METAL COMPOSITE
TANK MATERIAL AND DESIGN FOR STORAGE OF FLAMMABLE AND
COMBUSTIBLE FLUIDS
US2011186582
US2011186582
An improved fuel tank and method of forming a fuel tank utilize reinforced porous metal composite materials. In one embodiment, the composite material includes a fully dense, fluid-impermeable skin (1) combined with a porous metal baffle (2). The skin (1) and baffle (2) may be formed as a single monolithic system via electrodeposition of a nanolaminate material into at least a portion of open, accessible void space within a porous preform (e.g., a metal foam preform) and on the exterior surface of the preform to form the fluid-impermeable skin (1).
FIELD OF THE DISCLOSURE
[0001] This disclosure relates to an improved material, process, and design for constructing storage tanks for flammable and combustible fluids. Storage tanks produced using the disclosed methods and materials will a) reduce the risks of flame spread and explosion in the event of both low- and high-strain-rate (ballistic) impacts, b) allow for the production of arbitrary, conformable tank geometries, and c) provide enhanced strength-to-weight ratios over existing storage tanks for combustible and flammable fluid storage. Additional advantages afforded by the claimed material include resistance to chemical attack and enhanced dissipation of both heat and static charge.
BACKGROUND
[0002] Vehicles (automobiles, tanks, airplanes, boats, etc.) typically possess fuel tanks in which liquid fuel is free to move, or ‘slosh’, often resulting in a build up of static charge and an accompanying risk of ignition and subsequent explosion. Additionally, both liquid and gaseous fuel can escape unimpeded from conventional fuel tanks in the event of an accidental or intentional penetration of the tank. The risk of explosion and rapidly spreading flames resulting from either of these factors pose serious threats to the vehicle, vehicle occupants, and people or structures in the area.
[0003] In the case of liquid fuels, baffles comprising open cellular foams have been used extensively in the aircraft and racing industries to mitigate the effects of liquid fuel sloshing and leakage. One form of baffle, for example, comprises an open cellular plastic foam, such as SafeCrest® foam, available from Crest Foam Industries, Inc. Moonachie, N.J., USA. Such foams are generally applied inside of the fuel tank after construction via cut and placement, post placement expansion (see for example, U.S. Pat. No. 4,764,408) or spray foam application (see for example, www.crestfoam.com). The advantages of such foams include reduced fuel spillage and reduced atomization that results from fuel being trapped inside of the foam cells in case of a tank perforation. As a result, such fuel tank systems mitigate fireball occurrence.
[0004] The plastic foam baffles tend to chemically degrade over time, and the debris generated can plug fuel filter systems. The foam baffles also complicate fueling procedures as the fuel tends to foam on contact with the baffle system, thus limiting fueling rates. Debris may also build up and block the foam, thereby reducing fuel tank volume. Furthermore, while plastic foam baffle systems help mitigate spillage in the case of a tank penetration, these foams provide little to no structural reinforcement and therefore do not inhibit the penetration itself. Finally, they are neither thermally nor electrically conductive, and therefore cannot dissipate static charge or heat.
[0005] U.S. Pat. No. 4,844,974 describes electrically conductive, chemically resistant carbonaceous fibers which, when packed within a fluid storage vessel, prevent sloshing of the fluid and dissipate static electricity buildup. These fibers further serve to absorb liquid fuels, thereby reducing their mobility and slowing their combustion. While inhibiting flame spread and explosion, the materials of U.S. Pat. No. 4,844,974 provide minimal structural reinforcement, and therefore do not enhance resistance of the storage container to puncture.
SUMMARY OF THE DISCLOSURE
[0006] The present disclosure applies to storage of pressurized gases, especially those used as vehicle fuel where tank volume, weight, shape, and strength all contribute to the overall energy density of the gaseous fuel. By employing composite materials, and in particular composite materials including a nanolaminated alloy, higher strength-to-weight and strength-to-volume ratios can be achieved compared with conventional pressurized gas storage tanks, resulting in higher energy densities and greater vehicle traveling distance. Compressed hydrogen storage is one example of such an application.
[0007] One aspect of the present disclosure is to provide a material for the construction of storage tanks for combustible and flammable fluids which incorporates the benefits of an open cellular baffle system with the advantageous material properties of a nanolaminated alloy in order to protect against tank penetration and reduce the risk of flame spread and explosion in case of a tank penetration.
[0008] Another aspect of this disclosure is to provide a method for the production of said storage tanks which allows for control of the nanolaminate alloy composition such that, for example, highly corrosion and chemical resistant alloys can be incorporated into the design, specific structural and protective characteristics can be met, and/or specific tank geometries may be realized.
[0009] In yet another aspect, the present disclosure provides a design, employing said material, for a fuel tank which both resists penetration by ballistic impacts, prevents or lessens flame spread and explosion in the event of penetration, and prevents or lessens fuel foaming during fueling operations.
[0010] In a further aspect, embodiments described in the present disclosure are directed to a fuel tank. The fuel tank includes a porous metal baffle and a fluid impermeable vessel defining a fuel storage area. The porous metal baffle is disposed within the fuel storage area. Such embodiments can include one or more of the following features. The porous metal baffle can include a porous body defining an accessible, interior void structure. In some embodiments, a nanolaminate coating is disposed within the accessible, interior void structure. The nanolaminate coating can provide reinforcement to the porous body. In some embodiments, the nanolaminate coating is compositionally modulated. The nanolaminate coating can include a corrosion-resistant protective alloy, such as, for example, an alloy comprising about 70% Ni and about 30% Cu. In some embodiments, the fluid impermeable vessel comprises an exterior shell including a nanolaminated material. The nanolaminated material can include a corrosion-resistant protective alloy. The fuel tank can also include a force distributing layer and a ballistic penetration prevention layer disposed on the exterior shell of the vessel. In some embodiments, the porous metal baffle and the fluid impermeable vessel are integrally formed. In some embodiments, the porous metal baffle is formed from a consolidated preform, such as, for example, a foam, a fabric, or honeycomb structure. In other embodiments, the porous metal baffle is formed from an unconsolidated material, such as, a bed of particles or beads, or a fiber tow. In some embodiments, the fuel storage area of the fuel tank comprises at least about 0.5% metal foam by volume.
[0011] In another aspect, embodiments described in the present disclosure are directed to a method of producing a fuel tank. The method includes laying a conductive porous preform in contact with an inside surface of a fuel tank vessel; filling the vessel with an electrolyte bath including one or more electrodepositable materials; creating a current pathway by attaching a first electrode to the porous preform and disposing a second electrode in the electrolyte bath; and applying power to the first and second electrodes to form a nanolaminate coating on the porous preform. The method can further include melting or etching the porous preform to form a nanolaminate structure. In some embodiments, the nanolaminate coating is a corrosion-resistant protective alloy.
[0012] In another aspect, embodiments of the disclosure are directed to a method of producing a fuel tank. This method includes obtaining an electrolyte bath including one or more electrodepositable species; immersing a porous preform in the electrolyte bath; creating a current pathway by attaching a first electrode to the porous preform and a second electrode to the electrolyte bath; and applying power to the first and second electrodes to form a nanolaminate coating on the porous preform. In some embodiments, this method can further include applying one or more layers of conductive fabric on the nanolaminate coated porous preform; and depositing a second nanolaminate coating on the conductive fabric. In some embodiments, the method can also include melting or etching the porous preform to form a porous nanolaminate structure. The method can also feature a corrosion resistant nanolaminate coating.
[0013] In yet a further aspect, embodiments of the disclosure are directed to a method of manufacturing a functionally graded composite material. This method includes obtaining a first functionally graded porous preform; depositing a first nanolaminated material on the first functionally graded porous preform; positioning a second functionally graded porous preform in contact with the nanolaminated first functionally graded porous preform; and depositing a second nanolaminated material on the second functionally graded porous preform and the first functionally graded porous preform to fuse the first and second graded porous preforms. This method can further include, in some embodiments, positioning a third porous preform in contact with the nanolaminated second functionally graded porous preform and depositing a third nanolaminated material to fuse the third porous preform to the second functionally graded porous preform. Embodiments of this method can also feature functionally graded porous preforms that include a foam of radially graded pores per inch.
[0014] In another aspect, embodiments of the disclosure are directed to a composite material for use in the construction of a liquid transport vessel. The composite material includes a porous metal reinforcing material and a metal liner. The porous metal reinforcing material and the metal liner form a single monolithic system (i.e., the porous metal reinforcing material and metal liner are integrally formed).
[0015] Embodiments of this aspect of the disclosure can include one or more of the following features. The porous metal reinforcing material, in some embodiments, includes a substrate material defining an accessible interior void structure and an electrodeposited material at least partially disposed within the accessible interior void structure. The electrodeposited material can be compositionally modulated through its thickness to form an electrodeposit. The electrodeposit can have a modulation wavelength that is less than about 1 micron (e.g., 200 nanometers, 150 nanometers, 80 nanometers, 25 nanometers, 20 nanometers, 10 nanometers, 5 nanometers, 1 nanometer) within at least a portion of the electrodeposit. The electrodeposited material, in some embodiments, is a metal or metal alloy and can include at least one of nickel, iron, copper, cobalt, gold, silver, platinum, and combinations thereof. In another embodiment, the electrodeposited material includes a polymer. In some embodiments, the electrodeposit has a thickness that continuously increases through a portion of the preform.
[0016] In another aspect, embodiments of the disclosure are directed to a method for forming a fuel tank. The method includes providing a bladder in the form of a final fuel tank form; lining an interior of the bladder with a porous preform including an accessible interior void structure; connecting the porous preform to a first electrode; filling the bladder with a bath including at least two electrodepositable species; inserting a second electrode into the bath; and applying a voltage or current to the first electrode to electrodeposit a material within the accessible interior void structure of the porous preform.
[0017] Embodiments of this aspect of the disclosure can include one or more of the following features. The porous preform, in some embodiments, possess a gradient in porosity. That is, the porosity varies through the porous preform. In some embodiments the porous preform includes a consolidated material, such as, for example, a foam, a felt, or a honeycomb. In other embodiments the porous preform includes an unconsolidated material, such as, for example, a bed of particles or beads. The method can further include electrodepositing a compositionally modulated layer on an exterior surface of the porous preform. In some embodiments, the voltage or current applied to the first electrode varies with time.
BRIEF DESCRIPTION OF DRAWINGS
[0018] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure.
[0019] FIG. 1 is an illustration of a composite material in accordance with one embodiment of the present disclosure. This composite material includes an impermeable skin (i.e. liner) and a porous foam baffle (i.e., substrate).
[0020] FIG. 2A is an cross-sectional illustration of an embodiment of a reinforcement material applied to a porous substrate. This embodiment includes a carbon fiber tow porous substrate reinforced with a metal nanolaminate coating.
[0021] FIG. 2B is an illustration of another embodiment of a reinforcement material applied to a porous substrate. This embodiment includes a reticulated foam porous substrate reinforced with a metal laminate coating.
[0022] FIG. 2C is an cross-sectional illustration taken along line a-a in FIGURE. 2B showing a portion of the foam substrate with reinforcement material.
[0023] FIGS. 3A-3C are micrographs of a fracture surface of a metal nanolaminate deposited over a reticulated foam substrate, at a magnification of 24×, 100×, and 600×, respectively.
[0024] FIG. 4 is an illustration of an embodiment of a fuel tank in accordance with one embodiment of the present disclosure.
[0025] FIG. 5 is an illustration of a method of producing a fuel tank in accordance with one embodiment of the present disclosure. The method uses a conformal bladder bound to a porous preform baffle.
[0026] FIG. 6 is an illustration of another method of producing a fuel tank in accordance with one embodiment of the present disclosure.
[0027] FIG. 7 is an illustration of another method of producing a fuel tank.
[0028] FIGS. 8A-D illustrate a layered manufacturing scheme including functionally graded porous substrates. FIG. 8E illustrates an exploded perspective view of a first, second, third, and forth porous substrates preforms after deposition to join the substrates together.
[0029] FIG. 9 is an illustration of an enlarged cross-sectional view of a compositionally modulated electrodeposited material in accordance with another embodiment of the present disclosure.
[0030] FIG. 10 is an illustration of an enlarged cross-sectional view of a composite material in accordance with one embodiment of the present disclosure. This composite material includes a consolidated porous substrate with a compositionally modulated electrodeposited material disposed in at least a portion of an open, accessible void structure of the porous substrate.
[0031] FIG. 11 is an illustration of a cross-sectional view of the compositionally modulated material of FIG. 10 along one of the voids.
[0032] FIG. 12 is an illustration of an electroplating cell including a working electrode attached to the porous substrate.
[0033] FIGS. 13A, 13B, 13C, 13D and 13E are graphs showing electrodeposition conditions and resulting composition maps for the deposition conditions. FIG. 5A is a plot of applied frequency to a working electrode in an electrochemical cell versus time. FIG. 5B is a plot of applied amplitude to a working electrode in an electrochemical cell versus time. FIG. 5C is a plot of applied current density to a working electrode in an electrochemical cell versus time. FIG. 5D is an envisioned resulting deposit composition map corresponding to the applied current density give in FIG. 5C (i.e., one frequency modulation cycle of deposition). FIG. 13E is an envisioned composition map corresponding to application of ten frequency modulation cycles of deposition.
[0034] FIG. 14A is a graph showing a waveform of iron content in a nickel-iron compositionally modulated electrodeposited coating and FIG. 14B is the corresponding composition map.
[0035] FIGS. 15A-15C are illustrations of cross-sectional views of various embodiments of composite materials in accordance with the present disclosure. FIG. 15A is an illustration of a composite including an electrochemically infused particle bed having a particle distribution that gradually increases from the exterior surfaces of the composite into the center of the composite. FIGS. 15B and 15C are other illustrations of a composite including an electrochemically infused particle bed. In FIG. 15B, the particles have a repeating size distribution. In FIG. 15C, the particles have a graded distribution.
[0036] FIGS. 16A and 16B are illustrations of two separate embodiments of a compositionally modulated material disposed within the void structure between four particles.
[0037] FIG. 17 is an illustration of a cross-sectional view of an embodiment of a composite material including a nanostructured capping layer deposited on an exterior surface of a porous substrate.
[0038] FIG. 18 is an illustration of a cross-sectional view of an embodiment of a consolidated, conductive porous substrate with a tailored filing of a compositionally modulated electrodeposit coating disposed within its accessible void structure. Deposition conditions for this embodiment have been tailored to not only vary a thickness of the coating throughout the depth of the consolidated conductive porous substrate, but also to cap or seal the composite with a dense compositionally modulated layer that substantially closes off accessibility to the interior void structure.
[0039] FIG. 19 is an illustration of a flow cell for electrodepositing a compositionally modulated material into a void structure of an electrically conductive porous substrate.
[0040] FIG. 20 is an illustration of a flow cell for electrodepositing a compositionally modulated material into a void structure of an electrically non-conductive porous substrate.
DETAILED DESCRIPTION
[0041] Referring to the drawings, FIG. 1 illustrates one embodiment of the proposed baffle/liner fuel tank material. The fuel tank material comprises a fully dense (e.g., about 95% dense, 96% dense, 97% dense, 98% dense, 99% dense, 100% dense), fluid-impermeable skin 1 and a porous metal baffle material 2, such as a foam or honeycomb. The skin 1 and metal baffle 2 may be combined via glue, weld or other metal adhesion process, or, in an embodiment, the skin 1 and baffle 2 may be a single monolithic system formed via electrodeposition or other suitable method. In one advantageous embodiment, and in contrast to the sharp transition between baffle 2 and skin 1 shown in FIG. 1, the open cellular structure of the baffle will transition gradually to a completely closed off, fully dense, fluid-impermeable skin at the face.
[0042] The tank material can include, in one embodiment, a reinforcing material 3, such as a nanolaminated metal material that can be produced by electrodeposition (electroplating) under controlled, time-varying conditions. These conditions include one or more of the following: applied current, applied voltage, rate of agitation, and concentration of one or more of the species within the electroplating bath (e.g., a bath including one or more of an electrodepositable species such as nickel, iron, copper, cobalt, gold, silver, zinc, or platinum). Nanolaminations are defined here as spatial modulations, in the growth direction of the electrodeposited reinforcing material, in structure (e.g. crystal size, orientation, type), composition (e.g. alloy composition), or both. Nanolaminates include a modulation wavelength that is less than 1 micron—i.e., the modulation wavelength is nanoscale. (See International Patent Publication No. WO2007021980 for a further description of nanolaminate materials and electrodeposition of nanolaminate materials.) Metal nanolaminates can be applied over a variety of porous preforms such as honeycombs, fiber cloth or batting (woven or nonwoven), and reticulated foams (see FIGS. 2B, 2C, 3A, 3B, and 3C), most of which possess little structural integrity in their original form, and can therefore be easily shaped to the desired tank or component geometry prior to electrodeposition. In addition, metal nanolaminates can be deposited throughout a porous preform formed of an unconsolidated material (e.g., a bed of power or beads). Metal laminates can be deposited into the open, accessible interior void structure of a porous preform, as well as on an exterior surface of any preform. Furthermore, plating conditions can be controlled to effect both uniform nanolaminate growth throughout the preform, as well as preferential growth and densification near the external surface of the preform. That is, deposition of the nanolaminate material can be controlled such that the nanolaminates thickness increases throughout the preform (or at least a portion of the preform). In this fashion, both baffle and skin can be produced in a single production run, without removing the part from the plating tank.
[0043] FIG. 4 illustrates an example of a spherical fuel tank (fueling port not shown) with enhanced structural integrity and ballistic resistance. Note that the shape of the tank can be tailored for specific fit requirements. The shape of the fuel tank is shown in FIG. 4 as spherical for conceptual depiction only. An internal portion 4 of the fuel tank may be filled with an accessible porous reinforcing material such as foam or honeycomb, or may be left open. The interior portion 4 (shown in FIG. 4 as a metal foam) holds the fuel. In this embodiment, the interior portion 4 is made of at least 0.5% metal foam by volume. The porous interior portion 4 provides a wicking action which regulates fuel withdrawal, reduces spillage and explosion in case of breach. In addition the porous interior portion 4, provides structural support to the fuel tank. A fuel shell 5 formed of a fluid-impermeable material and located at the exterior surface of the interior portion 4 serves to prevent leakage of fuel from the interior portion as well as to provide secondary strike protection (e.g., puncture resistance). The exterior foam layer 6 absorbs and distributes force of an impact to protect the interior portion 4 and the external shell 7 serves to provide principal strike protection.
[0044] The fuel tank material may be produced as shown in FIG. 5 by adhering or laying a conductive porous preform 12 in contact with the inside surface of a conductive or non-conductive fuel tank bladder 13 to form a cathode 16. The bladder 13 is then filled with electrolyte bath 15 containing one or more electrodepositable materials. Next, a power supply 17 is connected to the porous preform 12 and another to an electrode (i.e., anode 18) positioned within the composite shell 14 defined by the bladder 13 and reinforcing foam 12. Power is applied to these electrodes 16, 18 such that the nanolaminated metal (or other electrodepositable material) forms on the surface of the porous preform 12. After the desired metal thickness is achieved, the preform may be melted or etched away, or it may be left in place.
[0045] As shown in FIG. 6 and FIG. 7, the material may also be produced by immersing a conductive porous preform 12 into an electrolyte bath 15 containing at least one electrodepositable material. The conductive porous perform 12 also serves as the cathode 16 in these electrochemical cells. Next, a power supply 17 is connected to the preform 12 and another to one or more electrodes 18 immersed in the electrolyte bath 15. In the embodiment illustrated in FIG. 6, the electrochemical cell includes an interior anode 18a and two auxiliary anodes 18b which conform to the exterior of the preform 12 to impart the desired electrodeposit onto the porous (in this embodiment, hollow) preform 12. Power is applied to these electrodes 16, 18 such that the metal (or other electrodepositable material) forms on the accessible surface of the preform. After the desired metal thickness is achieved, the preform 12 may be melted or etched away, or it may be left in place.
[0046] FIGS. 8A-D depicts a layered manufacturing scheme, which allows functional gradation of the porous preform in three dimensions. In FIG. 8A, a metal laminate is deposited over the accessible surface (i.e., exterior and accessible interior void structure) of a single layer of a functionally graded porous preform. The functionally graded porous preform shown in FIG. 8A is a radially graded pores per inch (PPI) foam. In FIG. 8B, a second functionally graded porous preform layer is stacked on the metal laminate coated first layer and deposition of metal laminate continues over the entire preform to fuse the first and second radially graded layers together. In FIG. 8C a third functionally graded porous preform is added and a metal laminate is deposited to join the first, second and third graded porous preforms together. In FIG. 8D a fourth porous preform is added and a nanolaminate is deposited to fuse the first, second, third and forth preforms together. FIG. 8E illustrates an exploded view of the first, second, third, and forth preforms (i.e., layers) after deposition. Advantages of this technique include reduced preform waste, more thorough control of deposit uniformity through the bulk (since the bulk comprises several stacked, sequentially plated thin layers), and the ability to control the spatial distribution of porous preform material as well as nanolaminated metal reinforcing material.
[0047] An advantageous embodiment of the present invention features a composite material with a corrosion-resistant protective alloy covering atop a nanolaminated reinforcement. The corrosion-resistant protective alloy can also be positioned at other locations (besides atop) throughout the nanolaminated reinforcement. One such protective alloy consists of 70% Ni and 30% Cu. Other electrodepositable metals and/or polymers and/or particles could be used to achieve specific material properties as desired.
Methods and Materials
[0048] In some embodiments, the coatings (e.g., fuel shell and exterior shell) as well as the foam/porous layers of the fuel tank can be formed utilizing electrodeposition techniques. In addition, in some embodiments, both the coatings and/or the foam layers can include compositionally modulated electrodeposited materials, such as, for example, nanolaminate coatings. Some exemplary electrodeposition techniques and materials are provided within this section entitled “Methods and Materials.” These techniques and materials are not meant to be exhaustive, but rather are merely illustrative of possible embodiments of the technology disclosed herein.
[0049] The term “compositionally modulated” describes a material in which the chemical composition varies throughout at least one spatial coordinate, such as, for example, the material's depth. For example, in an electrochemical bath including a nickel-containing solution and an iron-containing solution, the resulting compositionally modulated electrodeposited material 20 includes alloys having a chemical make-up according to NixFe1-x, where x is a function of applied current or voltage and mass flow of the bath solution. Thus, by controlling or modulating at least one of the mass flow of the bath solution or the applied current or voltage to electrodes, the chemical make-up of a deposited layer can be controlled and varied through its depth (i.e., growth direction). As a result, the compositionally modulated electrodeposited material 20 shown in FIG. 9 includes several different alloys as illustrated by layers 30, 32, 34, 36, and 38.
[0050] Referring to FIG. 9, layers 32 and 36 represent nickel-rich (x>0.5) deposits, whereas layers 30, 34, and 38 represent iron-rich (x<0.5) deposits. While layers 32 and 36 are both nickel rich deposits, the value for x in each of layers 32 and 36 need not be the same. For example, the x value in layer 32 may be 0.7 whereas the x value in layer 36 may be 0.6. Likewise, the x values in layers 30, 34, and 38 can also vary or remain constant. In addition to the composition of the constituents (e.g., Ni and Fe) varying through the depth of the electrodeposited material 20, a thickness of each of the layers 30 to 38 varies through the depth as well. FIG. 9, while not to scale, illustrates the change or modulation in thickness through the layers 30, 32, 34, 36, and 38.
[0051] FIG. 10 illustrates another embodiment of the composite material, shown here as composite material 10. In this embodiment, a porous substrate 12 is a consolidated porous body. That is, the porous substrate 12 in this embodiment is a unitary piece that includes a plurality of voids 25 that define an accessible, interior void structure. Examples of consolidated porous bodies include, foams, fabrics, meshes, and partially sintered compacts. The compositionally modulated material 20 is electrodeposited throughout the accessible, interior void structure to form a coating along the walls of the substrate 12 defining the voids 25.
[0052] Referring to FIG. 11, the compositionally modulated material 20 disposed within the plurality of voids 25 (as shown in FIG. 10) includes multiple alloys illustrated as distinct layers 30, 32, 34, and 36. As described above the compositionally modulated material 20 is varied in both constituent concentration (i.e., to form the different alloy layers making up the material 20) and in thickness of the layers. In the embodiment shown in FIG. 11, the nickel-rich layers 32 and 36 further include a concentration of particles disposed therein, thereby forming particle-reinforced composite layers. As shown in FIG. 11, layers 32 and 36 need not include the same concentration of particles, thereby allowing the compositionally modulated material 20 to be further tailored to provide optimal material properties. While not wishing to be bound by any particular theory, it is believed that increasing the concentration of the particles in a layer increases the hardness of that particular layer. The concentration of particles per layer can be controlled through modulating the flow rate of the bath during electrodeposition. The particles can have any shape, such as spherical particles, pyramidal particles, rectangular particles, or irregularly shaped particles. In addition, the particles can be of any length scale, such as for example, millimeter sized (e.g., 1 to 5 millimeter), micron-sized (e.g., 100 microns to 0.1 microns), nanometer sized (e.g., 100 nm to 1 nm). In some embodiments, 85% or more (e.g., 87%, 89%, 90%, 93%, 95%, 96%, 97%, 98%, 99%, 100%) of the nanosized particles have an average grain size within a range of 10 nm to 100 nm. In certain embodiments, 85% or more of the nanosized particles have an average grain size within a range of 20 nm to 50 nm, 30 nm to 50 nm, 10 nm to 30 nm, or 1 to 10 nm. Examples of some suitable particles include carbide particles, alumina particles, glass particles, polymer particles, silicon carbide fibers, and clay platelets.
[0053] To form or deposit the compositionally modulated electrodeposited material 20, the porous substrate 12 is submerged into an electrochemical cell. Referring to FIG. 12, an electrodeposition cell 50, in one embodiment, includes a bath 55 of two or more of metal salts, a cathode (i.e., working electrode) 60, an anode (i.e., a counter electrode) 65, and a power supply (e.g. a potentiostat) 70, which electrically connects and controls the applied current between the working and counter electrodes, 60 and 65, respectively. The cell 50 can also include a reference electrode 75 to aid the potentiostat 70 in accurately controlling the applied current by providing a reference base line current measurement. In general, when an electrical current is passed through the cell 50, an oxidation/reduction reaction involving the metal ions in the bath 55 occurs and the resulting product is deposited on the working electrode 60. As shown in FIG. 12, the porous substrate 12 is positioned in contact with the working electrode 60. For example, in certain embodiments, the porous substrate is formed of a conductive material and functions as an extension of the working electrode 60. As a result, the resulting product of the oxidation/reduction reaction deposits within the accessible interior void structure 25. In other embodiments, the porous substrate 12 is formed of a nonconductive material and thus, electrodeposition occurs at a junction between the working electrode 60 and the porous substrate 12.
[0054] In general, one of the advantages of the methods and resulting composite materials described in this disclosure is a wide range of choices of materials available for deposition into the interior void structure 25 of the porous substrate 12. For example, salts of any transition metal can be used to form the bath 55. Specifically, some preferred materials include salts of the following metals: nickel, iron, copper, cobalt, gold, silver, zinc, and platinum. In addition to the wide range of materials available, electrodeposition techniques have an additional advantage of easily modifiable processing conditions. For example, a ratio of the metal salts and other electrodepositable components, such as, for example, alumina particles, can be controlled by their concentration within the bath. Thus, it is possible to provide a bath that has a Ni:Fe ratio of 1:1, 2:1, 3:1, 5:1, 10:1 or 20:1 by increasing or decreasing the concentration of a Fe salt within the bath in comparison to the Ni salt prior to deposition. Such ratios can thus be achieved for any of the electrodepositable components. Where more than two electrodepositable components are provided, such ratios can be achieved as between any two of the components such that the overall ratios for all components will be that which is desired. For example, a bath with Ni, Fe and Cu salts could yield ratios of Ni:Fe of 1:2 and a Ni:Cu of 1:3, making the overall ratio of Ni:Fe:Cu 1:2:3. In addition, a bath with Ni salt and alumina particles could yield a ratio of Ni:Al2O3 of 2:1, 2:1, 1:2, 3:1 or 1:3 by increasing or decreasing the concentration of particles within the bath.
[0055] FIGS. 13A, 13B, and 13C illustrate applied conditions to the electrochemical cell 50 for depositing the compositionally modulated material 20. FIG. 13D illustrates a resulting composition map for the applied conditions shown in FIGS. 13A, 13B, and 13C. FIG. 13C shows the current density over a period of 130 seconds applied to the working electrode 60. The applied current drives the oxidation/reduction reaction at the electrode to deposit a material product having the form AxB1-x, where A is a first bath constituent and B is a second bath constituent. While FIG. 13C illustrates a current density range of between -20 to -100 mA/cm<2>, other current density ranges are also possible for example, a current density range of between about -5 to -20 mA/cm<2 >may be preferable in some embodiments.
[0056] Another way of defining the modulation of the compositions of the deposited alloys (AxB1-x, where x varies) is with respect to a composition cycle. A composition cycle 80 defines the deposition of a pair of layers. The first layer of the composition cycles is a A-rich and the second layer is B-rich. Each composition cycle has a wavelength. A value assigned to the wavelength is equal to the thickness of the two layers forming the composition cycle 80. That is, the wavelength has a value that is equal to two times the thickness of one of the two layers forming the composition cycle (e.g., ?=10 nm, when thickness of Ni-rich layer within the composition cycle is equal to 5 nm). By including one or more composition cycles the deposited material is compositionally modulating. In a preferred embodiment, the compositionally modulated electrodeposited material 20 includes multiple composition cycles 20 (e.g., 5 composition cycles, 10 composition cycles, 20 composition cycles, 50 composition cycles, 100 composition cycles, 1,000 composition cycles, 10,000 composition cycles, 100,000 composition cycles or more).
[0057] The applied current density as shown in FIG. 13C is determined from an applied variation in frequency of the current per time (FIG. 13A) in combination with an applied variation in amplitude of the current per time (FIG. 13B). Referring to FIG. 13A, an applied frequency modulation, shown here as a triangle wave, effects the wavelength of the composition cycles. As shown by comparing FIGS. 13A and 13D, the wavelength of the composition cycles decreases as the frequency increases. While FIG. 13A illustrates this effect with an applied triangle wave, any waveform (i.e., a value that changes with time) may be applied to control or modulate the frequency and thus control or modulate the thickness/wavelengths of the deposited material 20. Examples of other waveforms that may be applied to tailor the changing thickness/wavelength of each of the deposited layers/composition cycles include sine waves, square waves, sawtooth waves, and any combination of these waveforms. The composition of the deposit (i.e., x value) can also be further modulated by varying the amplitude. FIG. 13B illustrates a sine wave modulation of the applied amplitude of the current applied to the working electrode. By changing the amplitude over time, the value of x varies over time such that not all of the Ni-rich layers have the same composition (nor do all the Fe-rich layers have the same composition).
[0058] Referring to FIGS. 14A and 14B, in some embodiments, the value of x is modulated within each of the layers, such that the compositionally modulated electrodeposited material 20 is graded to minimize or mask composition discontinuities. As a result of applying one or more of the above deposition conditions, the compositionally modulated electrodeposited material 20 can be tailored to include layers that provide a wide range of material properties and enhancements. One such enhancement is an increase in hardness. Without wishing to be bound to any particular theory, it is believed that regions of nanolaminate material (i.e., regions in which all of the composition cycles have a wavelength less than about 200 nm and preferably less than about 80 nm) exhibit a superior hardness not achievable by the same materials at greater lengths scales. This superior hardness is believed to arise from an increase in the material's elastic modulus coefficient, and is known as the “supermodulus effect.” In certain embodiments, the compositionally modulated electrodeposited material 20 is deposited to include one or more regions, which provide the composite material 10 with the supermodulus effect. That is, the compositionally modulated electrodeposited material 20 disposed within the void structure 25 of the porous substrate 12 or on an exterior surface of a substrate includes one or more regions in which all of the composition cycles include wavelengths less than 200 nm, and preferably less than about 80 nm. In one embodiment, the wavelengths are less than about 70 nm. In another embodiment, the hardness of the composite material 10 is enhanced by including varying concentrations of particles (e.g., Al2O3, SiC, Si3N4) within an electrodeposited metal. For example, by increasing the concentration of Al2O3 particles dispersed within layers of an electrodeposited Ni metal, an increase in Vicker's Hardness from 240 VEIN to 440 VEIN is achievable.
[0059] In some embodiments, the compositionally modulated electrodeposited material 20 can include regions in which the composition cycles 80 include wavelengths less than 200 nm (and thus which may exhibit the supermodulus effect) and also include regions in which some portion (e.g., at least or about: 1%, 2%, 5%, 7%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 92% 95%, 97%, 99% and 100%) of the composition cycles 80 include wavelengths greater than 200 nm. The portion(s) of the composition cycles 80 that include wavelengths greater than 200 nm could also be represented in ranges. For example, the composition cycles 80 of one or more regions could include a number of wavelengths greater than 200 nm in a range of from 1-2%, 2-5%, 1-5%, 5-7%, 5-10%, 1-10%, 10-20%, 20-30%, 30-40%, 40-50%, 50-60%, 60-70%, 70-80%, 80-90%, 90-92%, 90-95%, 95-97%, 95-99%, 95-100%, 90-100%, 80-100%, etc., with the balance of the composition cycles being less than 200 nm in that region. Without wishing to be bound by any particular theory, it is believed that, as hardness increases, ductility decreases. As a result, in order to provide a composite material that is enhanced to include regions of increased hardness and regions of increased ductility, the compositionally modulated electrodeposited material 20, in some embodiments, can include one or more regions in which all of the composition cycles 80 have a wavelength of about 200 nm or less including wavelengths less than 1 nanometer, one or more regions in which all of the composition cycles have a wavelength greater than 200 nm, and/or one or more regions in which a portion of the composition cycles 80 have a wavelength of about 200 nm or less and a portion have a wavelength greater than 200 nm. Within each of those portions, the wavelengths also can be adjusted to be of a desired size or range of sizes. Thus, for example, the region(s) having composition cycles of a wavelength of about 200 nm or less can themselves have wavelengths that vary from region to region or even within a region. Thus, is some embodiments, one region may have composition cycles having a wavelength of from 80-150 nm and another region in which the wavelengths are less than 80 nm. In other embodiments, one region could have both composition cycles of from 80-150 nm and less than 80 nm.
[0060] In certain embodiments, the compositionally modulated material 20 is tailored to minimize (e.g., prevent) delamination of its layers during use. For example, it is believed that when a projectile impacts a conventional laminated material, the resulting stress waves may cause delamination or debonding due to the presence of discontinuities. However, the compositionally modulated electrodeposited material 20 described herein can include a substantially continuous modulation of both its composition (i.e., x value) and wavelength such that discontinuities are minimized or eliminated, thereby preventing delamination.
[0061] Referring to FIGS. 15A-15C, in addition to compositionally modulating the electrodeposited material 20 to form the composite 10, the porous substrate material 12 can also be made of a material that is modulated through its depth. For example, as shown in FIG. 15A, in one embodiment, the porous substrate 12 is formed of particles 15 that gradually increase in size from an exterior 100 of the compact to an interior 110 of the composite 10. The particles in such embodiments can range from, e.g., 5 nm on the exterior 100 to 50 microns in the interior 110, 5 nm on the exterior 100 to 10 microns in the interior 110, 5 nm on the exterior to 1 micron in the interior 110, 10 nm on the exterior 100 to 10 microns in the interior 110, or from 10 nm on the exterior 100 to 1 micron in the interior. The differently sized particles 15 contribute to the material properties of the composite 10. For example, smaller particles have a greater surface area energy per unit volume than larger particles of the same material. As a result, the porous substrate can be tailored to provide additional advantageous material properties to different regions of the composite 10. Referring to FIGS. 15B and 15C, the porous substrate 12 can have other particle arrangements to provide different material properties to the composite 10. For example, in FIG. 15B the particles have a repetitive size distribution and in FIG. 15C the particles have a graded distribution.
[0062] FIGS. 16A and 16B show an enlarged cross-sectional view of the compositionally modulated electrodeposited material 20 disposed between four adjacent particles 15 of a porous substrate 12. In FIG. 16A, the particles 15 forming the porous substrate 12 are non-conductive particles (e.g., alumina particles, glass particles). As a result of their non-conductivity, electrodeposition occurs between two electrodes disposed on either end of the porous substrate 12 and the compositionally modulated electrodeposited material 20 is deposited in a bottom-up fashion. Thus, the compositionally modulated electrodeposited material fills the entire void structure 25 between the four particles. In the embodiment shown in FIG. 16B, the particles 15 are electrically conductive. As a result, electrodeposition can occur within the conductive porous material to produce layers that are initiated at a particle/void interface 120 and grow inwards to fill at least a portion of the interior void structure 25.
[0063] In addition to electrodepositing into a porous preform, the compositionally modulated material 20 can also be deposited on the exterior surfaces 100 of the porous substrate 12 to form a nanolaminate coating (e.g., a fuel shell or an exterior shell for a fuel tank as shown in FIG. 4). For example, after the accessible interior void structure 25 is at least partially filled in the case of an electrically conductive porous substrate or substantially filled in the case of a non-conductive porous substrate, an additional or capping layer 150 can be deposited onto the substrate to seal off the interior porous structure 25 as shown in FIG. 17.
[0064] In certain embodiments, the filling of the accessible interior void structure 25 is tailored such that the thickness of the compositionally modulating electrodeposited material 20 varies throughout the composite 10. For example, FIG. 18 illustrates a composite material 10 formed of a porous conductive foam 12 and a NixFe1-x compositionally modulated material 20. The thickness of the compositionally modulated material 20 continuously increases (i.e., thickens) from the interior portion 110 of the porous substrate 12 to the exterior 100. To create this thickening, the current density during deposition is continuously increased. In addition to including the compositionally modulated material 20 disposed throughout the void structure 25 of the substrate 12, a dense layer of the compositionally modulated material, referred to as the capping layer 150 is further applied to the exterior 100 of the substrate 12 to close off the accessible pore structure 25.
[0065] Methods of forming the composite 10 using electrodeposition can include the following steps: (1) forming a bath including at least two electrodepositable components, (2) connecting the porous preform 12 to the working electrode 60, (3) inserting the porous preform 12, the working electrode 60, and the counter electrode 65 into the bath 55, and (4) applying a voltage or current to the working electrode 60 to drive electrodeposition.
[0066] In general, in one embodiment, the voltage or current applied to the working electrode 60 varies over time so that the compositionally modulated material is electrodeposited into the voids 25 of the porous substrate 12. Thus, in some embodiments, the voltage or current is applied to the electrode 60 with a time varying frequency that oscillates in accordance with a triangle wave. In other embodiments, the voltage or current is applied to the electrode with a time varying frequency that oscillates in accordance with a sine wave, a square wave, a saw-tooth wave, or any other waveform, such as a combination of the foregoing waveforms. The voltage or current can be applied for one waveform cycle as shown in FIG. 13A, or preferably for two or more cycles (e.g., three cycles, five cycles, 10 cycles, 20 cycles). FIG. 13E shows the envisioned composition map for a 10 cycle deposit.
[0067] In addition to controlling the voltage or current, other deposition conditions can also be monitored and varied to tailor the compositionally modulating material 20. For example, it is believed that the pH of the bath has an effect on upon the quality of the deposited material. Thus, in some embodiments, the pH of the bath is controlled during electrodeposition. For example, prior to deposition a pH set point (e.g., a pH of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14) or range (e.g., a pH of 1-2, 2-3, 3-4, 5-6, 6-7, 7-8, 8-9, 9-10, 10-11, 11-12, 12-13, or 13-14) is determined. During electrodeposition, the pH of the bath is monitored and if a difference from the set point is determined, pH altering chemicals, such as, for example, HCl or NaOH, are added to the bath to return the bath to its pH set point.
[0068] The concentration of the electrodepositable components in the bath can also be monitored and controlled. For example, concentration sensors can be positioned within the cell 50 to monitor the concentrations of the metal salts as well as any depositable particles within the bath. During electrodeposition of the compositionally modulated material 20, the concentrations of the depositable components (e.g., metal salts, particles) can become depleted or at least decreased from a predetermined optimal level within the bath. As a result, the timeliness of the deposition of the compositionally modulated material 20 can be effected. Thus, by monitoring and replenishing the concentrations of the depositable components electrodeposition can be optimized.
[0069] In certain embodiments, flow rate of the bath can be modulated or varied. As described above, both the applied current or voltage and the mass flow rate of the depositable components effects the x-value of the electrodeposit (e.g., NixFe1-x). Thus, in some embodiments, the flow rate of the bath containing the depositable components is varied in addition to the applied voltage or current to produce the modulation in the value of x. In other embodiments, the applied voltage or current remains constant and the flow rate is varied to produce the modulation in the value of x. The flow rate of the bath can be increased or decreased by providing agitation, such as, for example, a magnetically-controlled mixer or by adding a pump to the cell 50. By agitating the bath or by agitating the perform the mass transfer rate of the electrodeposited material is effected in that electrodepositable species may be more readily available for deposition thereby providing improved deposition conditions.
[0070] FIGS. 19 and 20 illustrate embodiments of an electrochemical cell 50 that includes a pump 200. In general, these cells 50 are referred to as flow cells because they force a bath solution through a porous substrate. Referring to FIG. 19, the flow cell includes a porous working electrode 60, which is also the porous electrically-conductive substrate 12, and a porous counter electrode 65. The working electrode 60, the counter electrode 65 and the reference electrode 75 are in communication and are controlled by the potentiostat 70. The bath fluid 55 including the depositable components is forced through the porous working electrode 60 (and thus the porous substrate 12) and the counter electrode 65 at a flow rate adjustable at the pump 200. Thus, in certain embodiments, the flow rate of the pump 200 can be controlled in accordance with a triangle wave, square wave, sine wave, a saw tooth wave, or any other waveform, such that the flow rate can be modulated to produce the compositionally modulated material 20. FIG. 20 illustrates another embodiment of a flow cell 50 for use with non-conductive porous substrates 12. In this cell 50, the working electrode 60 and the counter electrode 65 are disposed within a wall of the cell 50 and the bath fluid 55 is forced through the porous non-conductive substrate 12. Electrodeposition occurs in a bottom-up fashion, that is, the deposition of material 20 proceeds from the working electrode 60 to the counter electrode 65 substantially filling the void structure 25 along the way.
[0071] The methods and composite materials described herein can be tailored to provide the unusual combination of strength, ductility, and low-density. For example, the porous substrate 12 forming the matrix of the composite material 10 can be formed of a light-weight ceramic material or can include a relatively large amount (e.g., 40% by volume, 50% by volume, 60% by volume) of accessible interior void space 25. The compositionally modulated material 20 electrodeposited into the accessible, interior void space 25 can be tailored to provide strength at least in part through nanolaminate regions and ductility at least in part through micron or submicron sized laminated regions. These composite materials can be utilized in automotive applications, ballistic applications, or any other application that would benefit from this combination of material properties.
EXAMPLES
[0072] The following examples are provided to further illustrate and to facilitate the understanding of the disclosure. These specific examples are intended to be illustrative of the disclosure and are not intended to be limiting.
Example 1
[0073] A fuel tank for a vehicle can be formed to have an interior portion made from a preform of reticulated vitreous carbon, a fuel shell made of a nanolaminate coating including Ni and Fe, an exterior foam or porous layer formed of a conductive fabric, and an exterior shell including a Ni/Fe nanolaminate coating (which can either be identical to the fuel shell layer or have a different composition and/or structure than the fuel shell layer). Both the fuel shell and exterior shell nanolaminate coatings are formed by means of electrodeposition.
[0074] To form the fuel tank, a bath including 0.2M Ni(NH2SO3)2.4H2O, 0.2M FeCl2?4H2O, 0.40M H3BO3, 1.5 g/L sodium saccharin, 0.2 g/L sodium dodecyl sulfate, 1.0 g/L ascorbic acid, and enough sulfamic acid or nickel carbonate to attain a pH level of 3.00±0.01 is prepared. Anodes formed of titanium baskets including nickel S-rounds are obtained. The baskets are selected such that a nominal basket area is equal to or greater than a nominal workpiece area (i.e., the workpiece is the preform of reticulated vitreous carbon to be coated with nanolaminate). The baskets are positioned within the bath to optimize the uniformity of a current distribution over the workpiece.
[0075] The workpiece, which includes a 20 pores per inch reticulated vitreous carbon preform formed into a particular tank geometry (e.g., spherical), serves as the cathode in the electrodeposition process. After or right before the workpiece and the titanium basket anodes are submerged in the bath, a positive terminal of a power supply is connected in electrical contact with the baskets and a negative terminal of the power supply is electrically connected to the workpiece.
[0076] A filter pump with a 1-micron particle size cartridge is placed in fluid communication with the bath such that the tank volume can be turned over at least about 4 times per hour. An oscillator or other means of gently moving the workpiece back and forth within the bath is connected to the workpiece to provide high rates of mass transfer to the cathode as well as to dislodge bubbles that may form during electrodeposition.
[0077] Also connected to the bath are reservoirs of FeCl2 and sulfamic acid solution and necessary plumbing and flow control to maintain the bath concentration of iron at approximately 0.02M and the pH level at about 3.00 by addition of FeCl2 and sulfamic acid either by a steady predetermined flow rate or by means of a feedback loop.
[0078] After the bath is heated to and maintained at a temperature of about 110° F., electrodeposition of the fuel shell layer begins by applying a time-varying current waveform to the workpiece through the power supply according to the following conditions: (a) a current density at a working electrode varies in a square-wave with a nominal maximum plating current of 15 mA/cm<2 >and a nominal minimum plating current of 3 mA/cm<2>, based on the nominal area of the workpiece exposed to the plating bath (b) a duty cycle of approximately 12%, with an off corresponding to a current density of 3 mA/cm<2 >is utilized, and (c) a frequency modulation according to a triangle wave from a peak of 1 Hz to a minimum of 0.001 Hz, with a modulation frequency of 0.0001 Hz is selected.
[0079] Electrodeposition of the fuel shell layer occurs for approximately 7 days during which FeCl2 and sulfamic acid solutions are added to the bath to maintain the concentration of iron at about 0.02 M and a pH level of 3.00. In addition, the nickel concentration within the bath is monitored to ensure that it is not in excess of 0.3 M. When the concentration exceeds 0.3 M, an appropriate amount of the bath is removed and the quantities of the original bath solutions (e.g., 0.2M Ni(NH2SO3)2.4H2O, 0.2M FeCl2.4H2O, 0.40M H3BO3, 1.5 g/L sodium saccharin, 0.2 g/L sodium dodecyl sulfate, 1.0 g/L ascorbic acid, and enough sulfamic acid or nickel carbonate to attain a pH level of 3.00±0.01) and deionized water are added to bring the bath solution back to its original state.
[0080] After 7 days of electrodeposition using the above process, the workpiece is removed from the bath without turning off the power supply. A wrap or covering of a layer of a conductive fabric (such as, for example, a silverized nylon knit or a carbon non-woven fabric) is layered about the exterior of the workpiece (i.e., the workpiece now includes an interior portion formed of reticulated vitreous carbon, a fuel shell layer of Ni/Fe nanolaminate, and an exterior porous layer of a conductive fabric).
[0081] The workpiece is slowly reimmersed into the bath, and electrodeposition of an exterior shell layer of Ni/Fe nanolaminate is deposited using the process described above for about another 7 days. Once complete the vehicle fuel tank is removed from the bath and rinsed with deionized water.
Example 2
[0082] A small rectangular composite fuel tank including a 20 PPI (pores per inch) reticulated vitreous carbon foam preform and an electrodeposited compositionally modulated NiFe alloy was formed in a laboratory using the following procedure. A bath was prepared using 0.2M Ni(H2NSO3)2.4H2O, 0.04 M FeCl2.4H2O, 0.40M H3BO3, 1.5 g/L sodium saccharin, 0.2 g/L sodium dodecyl sulfate, 1.0 g/L ascorbic acid, and sulfamic acid to attain a pH of 3.00±0.01. A 10? by 10? by 1? piece of 20 PPI reticulated vitreous carbon foam preform was rigidly mounted in an insulating frame which suspended the preform in the frame's center by a finite number of small conducting elements, or contacts. The contacts were contained and insulated within the frame such that they did not come into contact with the electroplating bath once immersed, and terminated at a single bus located at the top edge of the insulating frame. This bus was in turn connected to two 10 gauge hooks which allowed the entire assembly to hang from a bus bar mounted across the top of a plating tank. The frame was designed to provide electrical contact to the preform while not disturbing the distribution of current over all of the preform's surfaces. Further, the frame provides heft which allows the frame-preform assembly to be immersed in the bath without buoyancy-induced misalignment.
[0083] The open-top plating tank had interior dimensions of 12? by 12? by 12?, and was spanned over its top by three bus bars separated by 31/2?. The frame-workpiece assembly was hung from the central bus bar. The two remaining bus bars each supported two titanium anode baskets filled with nickel S-rounds, with each basket measuring 9? tall by 1? thick by 3? wide. The titanium anode baskets were enclosed within a napped polypropylene anode bag to minimize the suspension of anodically formed particles in the plating bath. The plating solution was continuously recycled through a 10?, 1 micron filter pump such that the entire tank volume passed through the filter at least three times per hour.
[0084] The central, cathodic bus bar was connected to the negative terminal of a 1 kW power supply. The two anodic bus bars were connected to the positive terminal of the same power supply.
[0085] Once positioned within the bath, a time-varying current was applied to the workpiece. The time-varying current was designed to have the following waveform characteristics: (1) the current density—based on the nominal surface area of the preform's major faces (2×100 in)—varied in accordance with a square-wave having a maximum deposition current density of 15 mA/cm<2 >and a minimum deposition current of 3 mA/cm<2>; (2) a duty cycle of 0.12 with the “off” part of the cycle corresponding to a current density setting of 3 mA/cm<2>; and (3) a frequency modulation according to a triangle waveform having a peak of 1 Hz, a minimum of 0.001 Hz, and a modulation rate of 0.0001 Hz. The time-varying current was applied to the working electrode for three days while maintaining the bath's iron composition and pH at 0.02M and 3.0, respectively, by automated addback of iron chloride solution and sulfamic acid solution.
[0086] After three days, the preform was removed and wrapped several times in tight-weave silverized nylon cloth. The workpiece was then re-immersed in the plating bath and the plating regime described above was continued for another three days, after which the workpiece was removed and thoroughly rinsed in DI water.
Example 3
[0087] A small rectangular composite fuel tank including a 20 PPI (pores per inch) reticulated vitreous carbon foam preform and an electrodeposited nickel reinforcement was formed in a laboratory using the following procedure.
[0088] A commercial nickel sulfamate plating bath was purchased from Technic, Inc. A 10? by 10? by 1? piece of 20 PPI reticulated vitreous carbon foam preform was rigidly mounted in an insulating frame which suspended the preform in the frame's center by a finite number of small conducting elements, or contacts. The contacts were contained and insulated within the frame such that they did not come into contact with the electroplating bath once immersed, and terminated at a single bus located at the top edge of the insulating frame. This bus was in turn connected to two 10 gauge hooks which allowed the entire assembly to hang from a bus bar mounted across the top of a plating tank. The frame was designed to provide electrical contact to the preform while not disturbing the distribution of current over all of the preform's surfaces. Further, the frame provides heft which allows the frame-preform assembly to be immersed in the bath without buoyancy-induced misalignment.
[0089] The open-top plating tank had interior dimensions of 12? by 12? by 12?, and was spanned over its top by three bus bars separated by 31/2?. The frame-workpiece assembly was hung from the central bus bar. The two remaining bus bars each supported two titanium anode baskets filled with nickel S-rounds, with each basket measuring 9? tall by 1? thick by 3? wide. The titanium anode baskets were enclosed within a napped polypropylene anode bag to minimize the suspension of anodically formed particles in the plating bath. The plating solution was continuously recycled through a 10?, 1 micron filter pump such that the entire tank volume passed through the filter at least three times per hour.
[0090] The central, cathodic bus bar was connected to the negative terminal of a 1 kW power supply. The two anodic bus bars were connected to the positive terminal of the same power supply.
[0091] Once positioned within the bath, a DC current density of 3 mA/cm<2 >was applied to the workpiece—based on the nominal surface area of the preform's major faces (2×100 in<2>). Plating continued for three days while maintaining the bath chemistry at the manufacturer's recommended makeup concentrations.
[0092] After three days, the preform was removed and wrapped several times in tight-weave silverized nylon cloth. The workpiece was then re-immersed in the plating bath and the plating regime described above was continued for another three days, after which the workpiece was removed and thoroughly rinsed in DI water.
Example 4
[0093] A cylindrical composite fuel tank including a 80 PPI (pores per inch) reticulated vitreous carbon foam preform and an electrodeposited compositionally modulated NiFe alloy was formed in a laboratory using the following procedure. A bath was prepared using 0.2M Ni(H2NSO3)2.4H2O, 0.04 M FeCl2.4H2O, 0.40M H3BO3, 1.5 g/L sodium saccharin, 0.2 g/L sodium dodecyl sulfate, 1.0 g/L ascorbic acid, and sulfamic acid to attain a pH of 3.00±0.01. A cylindrical piece of 80 PPI reticulated vitreous carbon foam measuring 10? long and having a diameter of 3? was penetrated to a depth of 9 inches along its axis by a stainless steel tube having a diameter of 2?. The center portion of the foam contained within the tube was subsequently removed, and the free end of the tube was affixed to a rotator. A metal brush was placed in contact with the free end of the tube, and further connected to the negative terminal of a 1 kW power supply.
[0094] An open-topped plating tank having interior dimensions of 12? by 12? by 12? and spanned over its top by two bus bars separated by 7? was filled with plating bath. The two bus bars each supported two titanium anode baskets filled with nickel S-rounds, with each basket measuring 9? tall by 1? thick by 3? wide. The titanium anode baskets were enclosed within a napped polypropylene anode bag to minimize the suspension of anodically formed particles in the plating bath. The plating solution was continuously recycled through a 10?, 1 micron filter pump such that the entire tank volume passed through the filter at least three times per hour.
[0095] The two anodic bus bars were connected to the positive terminal of the same power supply.
[0096] The foam-encased portion of the assembly was immersed in the plating bath.
[0097] Once positioned within the bath, the workpiece was rotated at a time-varying rotation speed while a time-varying current was applied to the workpiece. The current waveform was designed to have the following waveform characteristics: (1) the current density—based on the nominal surface area of the preform—varied in accordance with a square-wave having a maximum deposition current density of 15 mA/cm<2 >and a minimum deposition current of 3 mA/cm<2>; (2) a duty cycle of 0.12 with the “off” part of the cycle corresponding to a current density setting of 3 mA/cm<2>; and (3) a frequency modulation according to a triangle waveform having a peak of 1 Hz, a minimum of 0.001 Hz, and a modulation rate of 0.0001 Hz. The time-varying rotation rate was synchronized with the current waveform, but varied such that the short-duration portion of the rotation rate waveform was 50 RPM and the long-duration portion was 200 RPM. The current was applied to the workpiece for three days while maintaining the bath's iron composition and pH at 0.02M and 3.0, respectively, by automated addback of iron chloride solution and sulfamic acid solution.
[0098] After three days, the preform was removed and wrapped several times in tight-weave silverized nylon cloth. The workpiece was then re-immersed in the plating bath and the plating regime described above was continued for another three days, after which the workpiece was removed and thoroughly rinsed in DI water.
Example 5
[0099] A composite fuel tank comprising a porous baffle material affixed to a nonporous shell may be formed in a laboratory using the following procedure.
[0100] A bath is prepared using 0.4M Ni(H2NSO3)2.4H2O, 0.04 M FeCl2.4H2O, 0.40M H3BO3, 1.5 g/L sodium saccharin, 0.2 g/L sodium dodecyl sulfate, 1.0 g/L ascorbic acid, 1-5 wt % magnetic fibers or particles (e.g. particles of iron, cobalt, nickel, or alloys thereof), and sulfamic acid to attain a pH of 3.00±0.01.
[0101] An open-topped plating tank having interior dimensions of 12? by 12? by 12? and spanned over its top by three bus bars separated by 31/2? was filled with plating bath. The central bus bars supported a magnetic preform shell of the desired shape, while the remaining two bars supported two titanium anode baskets filled with nickel S-rounds, with each basket measuring 9? tall by 1? thick by 3? wide. The titanium anode baskets were enclosed within a napped polypropylene anode bag to minimize the suspension of anodically formed particles in the plating bath. The plating solution was unfiltered.
[0102] The two anodic bus bars were connected to the positive terminal of a 1 kW power supply. The central bus bar was connected to the negative terminal of the same power supply.
[0103] After establishing electrical connections to the magnetic workpiece and the anodes, the workpiece was slowly immersed in the plating bath. The magnetic particles were drawn to the workpiece such that they formed a porous preform that became consolidated by the applied electroplate. The applied current waveform was designed to have the following waveform characteristics: (1) the current density—based on the nominal surface area of the preform—varied in accordance with a square-wave having a maximum deposition current density of 15 mA/cm<2 >and a minimum deposition current of 3 mA/cm<2>; (2) a duty cycle of 0.12 with the “off” part of the cycle corresponding to a current density setting of 3 mA/cm<2>; and (3) a frequency modulation according to a triangle waveform having a peak of 1 Hz, a minimum of 0.001 Hz, and a modulation rate of 0.0001 Hz. The current was applied to the workpiece for three days while maintaining the bath's iron composition and pH at 0.02M and 3.0, respectively, by automated addback of iron chloride solution and sulfamic acid solution. Also, magnetic fibers/particles were periodically added to the plating bath to build upon the existing porous baffle.
[0104] After three days, the preform was removed and wrapped several times in tight-weave silverized nylon cloth. The workpiece was then re-immersed in the plating bath. The plating bath during this latter portion of plating was continuously recycled through a 10?, 1 micron polypropylene filter cartridge such that the entire bath volume passed through the filter at least 3 times per hour. No additional magnetic fibers/particles were added during this portion of the deposition. After an additional three days of plating, the workpiece was removed and thoroughly rinsed in DI water.
LOW STRESS PROPERTY MODULATED MATERIALS AND
METHODS OF THEIR PREPARATION
CA2730252
CA2730252
The technology described herein sets forth methods of making low stress or stress free coatings and articles using electrodeposition without the use of stress reducing agents in the deposition process. The articles and coatings can be layered or nanolayered wherein in the microstructure/nanostructure and composition of individual layers can be independently modulated.
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application 61/078,668 filed July 7, 2008, which is hereby incorporated by reference in its entirety.
BACKGROUND
Stress free material using control of electrodepositing process One difficulty with the preparation of coatings articles produced by electrodeposition processes arises from the internal stress in the electrodeposited materials that can lead to the failure of coatings and articles. A variety of means have been used to reduce the stress in electrodeposited materials including the use of stress reducing agents such as saccharin in nickel plating, and thiourea for copper plating. The ability to electrodeposited materials, and particularly metals, in stress free or low stress form without the use of additives that can negatively impact the performance of electrodeposited materials could provide an advance to the material science of electroplating and electroforming of coatings and articles.
SUMMARY OF THE DISCLOSURE
This disclosure provides electrodeposition processes for the application of low stress or stress free coatings and the preparation of low stress or stress free articles. The low stress and stress free coatings and electroformed articles may be prepared as a single material that is unlayered, or as an electroformed coating or article that is comprised of layered or nanolayered metal(s) or metal alloy(s) without the use of additives for the reduction of stress. In one embodiment the technology described herein is directed to a method of applying a low stress or stress free coating to substrate, or of electroforming a low stress or stress free article using electrodeposition comprising the steps of: applying an electrical current to said substrate, said current having a time varying current density, wherein the current density is controlled as a function of time, said function of time comprised of two or more cycles wherein each cycle independently has a first time period and a second time period. In this embodiment the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, RA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1. In another embodiment the technology described herein is directed to a method of applying a low stress or stress free coating to substrate, or of electroforming a low stress or stress free article using electrodeposition comprising the steps of: (a) providing a bath including one or more electrodepositable species; (b) providing a substrate to be coated; (c) at least partially immersing the substrate in the bath, the substrate being in electrical communication with a power supply; and (d) applying an electrical current to said substrate, said current having a time varying current density. In this embodiment the current density is controlled as a function of time, and the function of time is comprised of two or more cycles wherein each cycle independently has a first time period and a second time period, where the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, (3A, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period is greater than 1. Embodiments described herein also provide coatings and articles comprising stress free or low stress materials electrodeposited without the use of stress reducing additives by the methods described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings are not necessarily to scale; emphasis is being placed upon illustrating the principals of the disclosure.
Figure 1 illustrates one cycle of a generic function used to control the current density in the electrodeposition of low stress or stress free coatings or electroform low stress or stress free articles. The figure indicates the area bounded by the function and a line representing zero current density for said first period by the "A" and the area bounded by the function and a line representing zero current density for said second period by "B," which are used to determine the ratio (3A.
Figure 2 Illustrates an alternative set of terminology that may be used to describe the generic function used to control the current density in the plating process, particularly where the function used is a sine wave function. Positive values of J (current density) are cathodic and reducing, whereas negative values are anodic and oxidizing. For net electrodeposition to take place with a sine wave function the value of (3 must be greater than one (i.e.. Jotiset must be greater than zero).
DETAILED DESCRIPTION
Materials deposited by electrodeposition must have low stress to avoid cracking or peeling in the plating process or subsequent use. Moreover if the electrodeposited materials contain thin or narrow features, then the stress must be tensile as compressive stress would likely result in buckling of the material. A good deal of stress is intrinsic to the plating process, and some systems such as Ag and Fe-Ni are notorious for their high stress. See e.g., Marc J. Maldou "LIGA and Micromolding" Chapter 4, The MEMS Handbook, 2nd edition, CRC Press, Edited by Mohamed Gad-el-Hak (2006).
While it is possible to relieve stress from electrodeposited materials by using stress reducing agents during their deposition, such agents not only add to the cost of final product, perhaps more importantly they can affect the performance and properties of the deposited materials. The processes described herein provide, among other things, an electrodeposition process that produces low stress coatings without the use of stress reducing agents. Embodiments of the processes described herein may be used to electroform articles where the process employs a mandrel as a substrate that can be separated from the electrodeposited materials. The processes may also be used to form a coating on a substrate that is comprised of a single layer of low stress or stress free electrodeposited material and in some embodiments, the process can be used to form multiple layers or graded layers of electrodeposited materials, one or more of which are layers of low stress or stress free electrodeposited materials. Stress in a coating or layer may refer to the tendency of a material to curl or deform, causing it to peel away from the substrate onto which it is deposited. Tensile and compressive stresses in a coating or layer result in concave and convex delamination, respectively. Stress in an electrodeposited coating or article may be evaluated by any suitable means in the known in the art. For purposes of this disclosure, low stress coatings and articles are those that can maintain contact with a rigid substrate during electrodeposition when the bond strength is less than 400 MPa, or, more preferably less than 350MPa, 300MPa, 250MPa, 200MPa, 150MPa, 100 MPa, 60 MPa, 40 MPa, 30 MPa, 20 MPa, or l OMPa. For the purposes of this disclosure stress free means that the coating or article has a level of stress that is at, or below, the level of measurement, and which does not affect the ability of the article to maintain contact with the substrate during electrodeposition.
The stress of an electrodeposited material also may be characterized using conventional methods such as the bent strip method and commercially available testing equipment such a Model 683 deposit stress analyzer, available from Specialty Testing and Development Co., PA. For purposes of this disclosure, low stress coatings, layers, and articles have less than 400 MPa, or, more preferably less than 350MPa, 300MPa, 250MPa, 200MPa, 150MPa, 100MPa, 80 MPa, 60 MPa, 40 MPa, 30 MPa, 20 MPa, or l OM Pa of stress as assessed by the bent strip method. For the purposes of this disclosure, where a bent strip test is employed as means of assessing stress, "stress free" means that the coating, layer or article has a level of stress that is at, or below, the level of measurement in the bent strip test. For the purposes of this disclosure, "electrodeposition" defines a process in which electricity drives formation of a deposit on an electrode (e.g., a substrate) at least partially submerged in a bath including a component or species, which forms a solid phase upon either oxidation or reduction. The terms electrodeposition or electrodeposited include both electrolytic deposition (e.g., reduction of metal ions to metals) and electrophoretic deposition. For the purposes of this disclosure, "electrodepositable species" define the constituents of a material deposited using electrodeposition.
Electrodeposited species include, without limitation, metal ions forming a metal salt. Particles which are deposited in a metal matrix formed by electrodeposition, polymers and metal oxides can also be electrodeposited. Organic molecules (e.g., citric acid, malic acid, acetic acid, and succinic acid) may also be co-deposited with other electrodepositable species. For the purpose of this disclosure, current density is the current (generally in amperes) per unit area of a substrate upon which material is to be electrodeposited. Where current densities are stated to be positive, they are cathodic (reducing) currents and negative current densities are anodic (oxidizing) currents. For the purpose of this disclosure, the average current density for an electrodeposition process is taken as the integral of the current density versus time curve describing the process, divided by the total time and has the units of charge per unit area per unit time. Average current density can be calculated for one or more cycles of the function used to control current density in the electrodeposition processes described herein.
For the purpose of this disclosure, nanolayered means layered material having at least one layer with at least one dimension (usually thickness) greater than 0.5 nm and less than 1,000 nm. For the purpose of this disclosure, an electrolyte can be an aqueous solution or an ionic liquid, either of which may comprise one or more electrodepositable species. In one embodiment a method of producing low stress or stress free coatings on a substrate, or of electroforming an article on a substrate (e.g., a mandrel) using electrodeposition comprises: applying an electrical current to said substrate, said current having a time varying current density, wherein the current density is controlled as a function of time, said function of time comprised of two or more cycles wherein each cycle independently has a first time period and a second time period, where the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, (3A, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1.
In another embodiment a method of producing low stress or stress free coating to substrate, or of electroforming an article on a substrate (e.g., a mandrel) using electrodeposition comprises: (a) providing a bath including one or more electrodepositable species; (b) providing a substrate to be coated; (c) at least partially immersing the substrate in the bath, the substrate being in electrically communication with a power supply; and (d) applying an electrical current to said substrate, said current having a time varying current density, wherein the current density is controlled as a function of time, said function of time comprised of two or more cycles wherein each cycle independently has a first time period and a second time period, and where the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, RA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1. While the description provided in Figure 1 is not to be viewed as limiting the type of functions that may be employed to produce low stress or stress free coatings and articles by electrodeposition, that figure illustrates exemplary functions that may be employed to produce low stress or stress free materials through electrodeposition.
The embodiments described above may be better understood by reference to that figure. As positive current density is defined as a reducing cathodic current for the purposes of this disclosure, ratio (3A (Beta based on the integrated areas) must be greater than 1 for a cycle in order for there to be a net deposition of reducible materials (e.g. metal cations) at the cathode in the methods forming low or stress free coatings and articles described herein. The value of RA may effectively be any value greater than 1 and less than infinity for any cycle of the of the method but more typically (3A will be between a value that is greater than 1 and less than 100, or greater than 1.001 and less than 100, or greater than 1.01 and less than 100, or greater than 1.05 and less than 100, or greater than 1.1 and less than 100. In some embodiments the value of (3A is greater than a value selected from 2, 4, 8, 10, 20, 50, 100, 200, 400, 800, 1,000, or 10,000; in such embodiments the value of RA may be limited by an upper value of 100,000. In other embodiments the value of the ratio (3A may have a value greater than 1, or 1.01, or 1.05 or 1.1 and less than a value independently selected from 1.2, 1.25, 1.3, 1,35, 1.4, 1.45, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.4, 2.6, 2.8, 3.0, 3.5, 4, 6, 8, 10, 15, 20, 25, 50, 100, 200, 400, 800, 1,000, or 10,000. In some embodiments the value of RA within a range selected from: 1.01 to 2, 1.01 to 1.7, 1.01 to 1.6, 1.01 to 1.5, 1.01 to 1.4, 1.01 to 1.3, 1.01 to 1.2, 1.1 to 1.5, 1.1 to 1.6, 1.1 to 1.7, 1.1 to 1.8, 1.3 to 1.5, 1.3 to 1.7, 1.3 to 1.9, 1.5 to 1.7, 1.5 to 1.8, 1.5 to 1.9, 1.5 to 2.0, 1.6 to 1.9, 1.6 to 2, 1.7 to 1.9, 1.8 to 2, 1.5 to 8, 1.5 to 6, 2 to 40, 2 to 20, 2 to 10, 4 to 40, 1.1 to 50, or 2 to 50.
The number of cycles, each of which includes first period of electrodeposition and a second period of oxidation (etching or dissolution), used to apply a coating or to prepare an article using the methods described herein depends upon the thickness of the desired coating or article and the characteristics of the cycle employed (e.g., total passed charge and RA which represents the ratio of the material deposited to the material removed in a cycle). In some embodiments the function used in the electrodeposition process has 3 or more cycles, 10 or more cycles, 50 or more cycles, 100 or more cycles, 200 or more cycles, 500 or more cycles, 1,000 or more cycles, 2,000 or more cycles, 5,000 or more cycles, 10,000 or more cycles, 20,000 or more cycles, 50,000 or more cycles, 100,000 or more cycles, 200,000 or more cycles, 400,000 or more cycles, 500,000 or more cycles, 750,000 or more cycles, or 1,000,000 or more cycles.
While current density is controlled as a function of time in the electrodeposition processes described herein, the function for the individual cycle need not, but can, be the same. In some embodiments the function is identical for each cycle (although other parameters including the temperature and plating bath composition can be varied). In other embodiments the same function may be applied for one cycle or over a series of consecutive cycle followed by the application of a different function (with or without a change in the other parameters). In some embodiments the function applied for the low stress or stress free electrodeposition process is identical for 2, 3, 4, 5, 10, 20, 50, 100, 250, 500, 1,000, 5,000, 10,000, 20,000, 50,000, 100,000, 200,000, 500,000 consecutive cycles and the other plating parameters are also held constant (do not change). In other embodiments, the function applied for the low stress or stress free electrodeposition process is identical for 2, 3, 4, 5, 10, 20, 50, 100, 250, 500, 1,000, 5,000, 10,000, 20,000, 50,000, 100,000, 200,000, 500,000 consecutive cycles and one or more, or two or more, or three or more plating parameters (e.g., plating temperature, bath composition, or the concentration of the electrodepositable species in the bath) varied for one or more of the cycles.
In another embodiment the function employed for the electrodeposition processes described herein has 2, 3, 4, 5, 7, 10, 15, 20, 25, 50, 100, 200, 500, or 1,000 consecutive cycles wherein the function is employed in the electrodeposition process is not identical for those consecutive cycles. In one variation the function is varied between a first function and a second function for alternate cycles. In another variation the function is varied from a first function to second function to a third function over three consecutive cycles. In some embodiments the value of the ratio (3A can be varied. In such embodiments, RA may be varied for 2, 3, 4, 5, 10, 20, 50, 100, 250, 500, 1,000, 5,000, 10,000, 20,000, 50,000, 100,000, 200,000, 500,000 or more consecutive cycles. In those embodiments where RA is increased or decreased from a first value to a second value by incrementally changing (3A, the disclosed methods may be used to create coatings or articles that vary from a first property or composition to a second property or composition in a continuous fashion (e.g., graded materials). The functions describing the change in current density with respect to time for a cycle of electrodeposition may be of virtually any form. In some embodiments the function is one that has a discontinuous first derivative with respect to time. Such functions include square wave, rectangular wave, triangular wave, or saw tooth wave forms possessing a DC offset.
In other embodiments the function describing the change in current density with respect to time may have a continuous first order derivative. In other embodiments such functions may have a continuous first order derivative with respect to time. Functions with continuous first order derivatives include shifted sine wave, shifted cosine wave, and other periodic wave type functions possessing a DC offset. Shifted sine wave functions, which are a special case of the general wave forms used to control the current density, may be described using three parameters, the offset current density, the frequency and the peak to peak current density used for the plating process. See Figure 2, which describes the terms that can be used with a "shifted sine wave" that has been shifted vertically on the current density axis by the application of an offset current density. For shifted sine wave functions a value 0, which is the ratio of the peak cathodic current density to the absolute value of the peak anodic current density may be defined. See Figure 2 and associated text. Where shifted sine or shifted cosine wave forms are used they are offset such that ratio (3A or (3 will be greater than 1, resulting in net electrodeposition of material at the cathode. In other embodiments the sine or cosine waves may be modified such that the amplitudes for the wave forms in the range of 0 to 180 and the range 180 to 360 degrees is different, resulting in a (3A that is greater than one. In some embodiments wave forms other than shifted sine waves and square (rectangular) waves with DC offsets may be employed, and part or all of any method described herein may be conducted provided that the wave form utilized is not a sine wave or a square (rectangular) wave with a DC offset.
Hence, any of the methods of this disclosure may be carried out with the proviso that when current density is controlled as a function of time, the function is not a sine wave or a square or rectangular wave form. The length of time for each cycle of the electrodeposition processes described herein may be the same or different, with the length of time varying independently for each cycle. In some embodiments the function describing the deposition process may have I to 4,000, 1 to 2,000, 1 to 800, 1 to 400, 1 to 200, 1 to 100, 1 to 10, 2 to 50, 3 to 75, 10 to 200, 50 to 300, or 100 to 400 cycles per second (Hz). In general, the frequency of the wave form (e.g., sine wave, square wave, or triangular wave) will vary from about 0.01 to about 1,000 Hz, with ranges typically being from about 10 to about 400 Hz. The peak anodic and cathodic currents, which are the maximum currents applied to a substrate during the periods of electrodeposition and oxidation (etching) during each cycle of the functions used to control current density, may also be modulated. Generally the absolute value of peak cathodic and anodic currents can be independently varied from about 1 to about 2,000 mA/cm2, with typical ranges being from about 10 to about 300 mA/cm2 or from about 60 to about 100 mA/cm2. The methods of electrodepositing low stress or stress free coating or electroforming articles may be used with a broad variety of electrodepositable species. In some embodiments the bath used for electrodeposition may contain only one electrodepositable species.
In some embodiments where the bath contains only one electrodepositable species the electrodepositable species is selected from the group consisting of. nickel, iron, cobalt, copper, zinc, manganese, platinum, palladium, rhodium, iridium, gold, aluminum, magnesium, and silver. In some embodiments where the bath contains only one electrodepositable species the electrodepositable species is selected from the group consisting of. nickel, cobalt, copper, zinc, manganese, platinum, palladium, rhodium, iridium, gold, aluminum, magnesium, and silver. In other embodiments where the electrolyte bath contains only one electrodepositable species the electrodepositable species is selected from the group consisting of: nickel, cobalt, manganese, platinum, palladium, rhodium, iridium, and silver. In still other embodiments where the bath contains only one electrodepositable species the electrodepositable species is selected from the group consisting of. nickel, cobalt, copper, zinc, manganese, gold, and silver. In still other embodiments, the methods of electrodepositing low stress or stress free materials may be practiced with the proviso that the electrodepositable species is not iron when the bath (electrolyte) contains only one electrodepositable species of metal; in such embodiments the bath (electrolyte) may further not include stress reducing agents (e.g., thiourea or saccharin).
In some embodiments the electrolyte bath (electrolyte) used for electrodeposition may contain two or more, or three or more, or four or more electrodepositable species. In some embodiments where the bath (electrolyte) contains two or more, or three or more, or four or more electrodepositable species, at least one electrodepositable species is selected from the group consisting of: molybdenum, tungsten, nickel, iron, cobalt, copper, zinc, manganese, platinum, palladium, rhodium, iridium, gold, aluminum, magnesium, and silver. In other embodiments at least one electrodepositable species is selected from the group consisting of: molybdenum and tungsten. In embodiments, where the bath (electrolyte) for electrodeposition contains two or more, or three or more, or four or more electrodepositable species, the methods of electrodepositing low stress or stress free materials may be practiced with the proviso that the electrodepositable species is not iron.
In some embodiments the material to be deposited is an alloy comprising nickel having greater than about 60% 70%, 75% 80%, 85% 90% or 95% of the electrodeposited material as nickel on a weight basis. In other embodiments the material to be deposited will be an alloy comprising nickel and iron having greater than about 55%, 60%, 70%, 75% 80%, 85% 90% or 95% of the electrodeposited material as the iron with the remainder made up of either nickel, or nickel and up to 5% other metals on a weight basis. In another embodiment the material to be deposited is an alloy comprising chromium, iron, and optionally nickel. In such alloys the chromium is present as 11-25% of the electrodeposited material, nickel is present from 0-20% of the electrodeposited materials, with the remainder made up of either iron, or iron and up to 5% other metals on a weight basis.
In still another embodiment the material to be deposited is an alloy comprising copper and zinc. In such alloys the copper is present at 1-95% of the electrodeposited material, preferably between 50% and 80%, with the remainder made up of either zinc, or zinc and up to 10% other metals on a weight basis. In still another embodiment the material to be deposited is an alloy comprising copper and tin. In such alloys the copper is present at 1-95% of the electrodeposited material, preferably 11 % to 13%, with the remainder made up of either tin, or tin and up to 10% other metals on a weight basis. In yet another embodiment the material to be deposited is an alloy comprising copper and aluminum. In such alloys the copper is present at 1-25% of the electrodeposited material, with the remainder made up of either aluminum, or aluminum and up to 10% other metals (such as magnesium) on a weight basis. In one embodiment chromium may be electrodeposited alone or as an alloy wherein chromium comprises greater than 50% of the electrodeposited material on a weight basis. In methods of electrodepositing chromium the chromium may be electrodeposited from either a Cr+3 or Cr+6 salt.
One embodiment provide for the electrodeposition of chromium as an alloy with iron, wherein the chromium comprises 1%-75% of the electrodeposited material on a weight basis with the remainder made up of either iron, or iron and up to 10% other metals on a weight basis. In such an embodiment the chromium may be electrodeposited from a Cr+3 salt. In still other embodiments, the material to be electrodeposited is an alloy comprising a metal selected from molybdenum, tungsten, nickel, iron, cobalt, copper, zinc, manganese, platinum, palladium, rhodium, iridium, gold, aluminum, magnesium, and silver; wherein greater than about 40%, 50% 60% 70%, 75% 80%, 85%, 90%, or 95% of the electrodeposited alloy is comprised of the selected metal. Other embodiments provide for the electrodepositing of iron with an organic molecule (e.g., citric acid, malic acid, acetic acid, or succinic acid). In such embodiments the organic molecule may comprise up to 2% of the total weight of the deposited material with the remainder made up of either iron, or iron and up to 10% other metals on a weight basis.
In some embodiments where the system (electrolyte) contains one or more electrodepositable species, those species may be the same electrodepositable species for the entirety of electrodeposition processes (the same species for all cycles). In other embodiments where the system contains one or more electrodepositable species, the composition of the bath used for electrodeposition may be changed so that different species or mixtures of electrodepositable species are present for different portions of the electrodeposition processes (i.e., to form a material that is compositionally modulated throughout its growth direction). In addition to varying composition of the electroplating media (bath), a variety of electrodeposition parameters can be modulated while still electrodepositing low stress or stress coatings or electroforming low stress or stress free articles. In some embodiments one or more of the electrodeposition parameters that can be modulated in one or more independently selected cycles, (whether those cycles are consecutive or not) are selected from: peak positive current density; the length of time of said first time period; the peak negative current density; the length of time of said second time period, the average current density, electrodeposition temperature (temperature of the bath) or the composition of the electrodeposition media (e.g., electrodeposition bath) may be. In other embodiments, one or more, or two or more, parameters selected from: the peak positive current density; the length of time of said first time period; the peak negative current density; the length of time of said second time period, or the average current density may be modulated in one or more, or two or more, independently selected cycles.
In still other embodiments, one or more, or two or more, parameters selected from the temperature of the electrodeposition media (bath) or the composition of said the bath may be modulated in one or more, or two or more, independently selected cycles. Embodiments of the methods described herein may be employed to produce low stress or stress free coatings and articles that may consist of one layer (material having a single type of structure and composition) in addition to coatings and articles that are layered or nanolayered. Layers and nanolayers present in the coatings and articles described herein need not arise from single cycles of the function used to control the electrodeposition process, instead, layers or nanolayers may arise from the application of numerous cycles of a function used to control electrodeposition. Thus, in some embodiments, the methods described herein may be used to develop layered or nanolayered coatings and articles by utilizing different wave forms in combinations. For example, a single composition may be deposited as a low stress or stress free layer utilizing numerous cycles of a sine wave function, followed by the deposition of a next layer of the same composition utilizing numerous cycles of a saw tooth wave form. Alternatively, low stress or stress free layers may be built up by the application of numerous cycles of specific function describing the electrodeposition of a first composition followed by the use numerous cycles of the same function to apply a layer of different composition or a layer of the same composition at a different temperature. Embodiments of the methods described herein are particularly useful as they permit the electrodeposition and electroforming of low stress or stress free coatings and articles without the use of stress reducing agent; however, where desirable it is possible to use the methods describe above in combination standard electrodeposition process that either do not control stress or use stress reducing agents. Thus, in addition to the deposition of layers of a substance (e.g., a metal) using low stress or stress free electrodeposition as described herein, it is possible to deposit layers of low stress or stress free materials utilizing stress reducing agents or by standard electrodeposition (e.g., DC electroplating). In some instances, such as where control of defect propagation or the direction of corrosive decomposition of coatings is desired, it may be desirable to prepare layered or nanolayered materials that have repeating (e.g., alternating) layers of. stress free and low stress materials; low stress or stress free materials alternated with layers of uncontrolled stress materials; or layers of stress free, low stress and uncontrolled stress materials. A variety of substrates for electrodeposition may be employed in the methods described herein. While the substrate may comprise a solid, conductive material (such as a metal object to be coated), other substrates are also possible. For example, instead of being solid, the substrate may be formed of a porous material, such as a consolidated porous substrate, such as a foam, a mesh, or a fabric. Alternatively, the substrate can be formed of an unconsolidated material, such as, a bed of particles, or a plurality of unconnected fibers. In some embodiments, including for example, embodiments which utilize electrodeposition, the substrate is generally formed from a conductive material or a non- conductive material which is made conductive by metallizing. In other embodiments, the substrate may be a semi-conductive material, such as a silicon wafer, or a nonconductive material, such as a ceramic or plastic composite. Where it is desirable to prepare an article through the use of electroforming, a solid conductive mandrel that can be separated from the electroformed materials may be employed (i.e., titanium or stainless steel mandrel). The electrodeposition methods described herein may be used without etching substrates prior to the application of low stress coatings without the use of additives in the electrodeposition process (e.g., the bath) to relieve stress. The methods of coating a substrate described herein may be utilized without the use of etching by electrical current, that is to say the application of a net negative (anodic current) to the substrate prior to (or immediately prior to) the application of a low stress coating. Similarly, the methods of coating a substrate described herein may be utilized without the use of etching by chemical means prior to (or immediately prior to) the application of a low stress coating without the use of additive to relieve stress. Some embodiments of this present disclosure are directed to a coating or article produced by the methods of electrodepositing low stress or stress free materials described herein that do not require the use of stress reliving agents. In some embodiments, a coating or article comprises a single low stress or stress free layer of electrodeposited materials that has not been deposited using stress reducing agents. In other embodiments, a low stress or stress free coating or article of the present technology comprises: a first material having a first composition and defined by one or more of a first composition, a first average grain size, a first grain boundary geometry, a first crystal orientation, and a first defect density; and a second material having a second composition and a second nanostructure defined by one or more of a second composition, a second average grain size, a second grain boundary geometry, a second crystal orientation, and a second defect density. In still another embodiment, a low stress or stress free coating comprises: a first material having a first composition and a first nanostructure defined by one or more of a first composition, a first average grain size, a first grain boundary geometry, a first crystal orientation, and a first defect density; and a second material having a second composition and a second nanostructure defined by one or more of a second composition, a second average grain size, a second grain boundary geometry, a second crystal orientation, and a second defect density; with the proviso that the second composition is the same as the first composition while one of the first average grain size differs from the second average grain size, the first grain boundary geometry differs from the second grain boundary geometry, the first crystal orientation differs from the second crystal orientation, and the first defect density differs from the second defect density.
In some embodiments, property modulated coatings and articles are provided comprising a plurality of alternating layers, in which one or more of those layers are low stress or stress free layers that have specific mechanical properties, such as, for example, tensile strength, elongation, hardness, ductility, and impact toughness, and where the specific mechanical properties are achieved by altering the nanostructure of those layers. Examples of such are provided in Examples 1 and 2. In general, tensile strength may be controlled through controlling frequency of a signal used for electrodepositing a material. In general, percentage of elongation of a material can also be controlled through frequency. In general, hardness, ductility, and impact toughness can be controlled through controlling deposition temperature. Other methods for controlling tensile strength, elongation, hardness, ductility and impact toughness are also envisioned. The structure of low stress and stress free electrodeposited materials may also be controlled in order to produce materials with desired properties. Smaller grain sizes, which can range, e.g., from about 0.5 nanometers to about 100 nanometers, generally will yield layers that exhibit high impact toughness. Large grain sizes, which generally will be greater than 1,000 nanometers, such as, for example, 5,000 or 10,000 nanometers, will generally produce layers that provide greater ductility. Of course, the grain sizes will be relative within a given group of layers such that even a grain size in the intermediate or small ranges described above could be deemed large compared to, e.g., a very small grain size or small compared to a very large grain size. Generally, such grain sizes can be controlled through process parameters, such as, for example deposition temperature (e.g., electrodeposition bath temperature). To modulate grain size utilizing temperature control, a first layer defined by large grains can be formed by increasing the deposition temperature and a second layer defined by smaller grains can be formed by decreasing the temperature. The thickness of the individual layers in the coatings and articles can range from about 0.1 nanometer to about 10,000 nanometers or more. Layer thickness may range from about 5 nanometers to 50 nanometers, although varied thicknesses are expressly envisioned. Coatings and articles prepared by the methods described herein may contain a single layer or any number of desired layers, including a number of layers within a range selected from: 2- 10, 10-20, 20-30, 30-50, 50-100, 2-500, 100-500, 2-1,000, 500-1,000, 1,000- 5,000 5,000- 10,000, or 2-10,000 or even more layers. Each layer may be independently created with a desired composition, thickness, and nanostructure/microstructure and with each layer being independently chosen to be of a low stress or stress free nature.
The coatings and articles described herein may be used separately or as part of other coatings and articles and may be incorporated into laminated structures. In addition, the methods of preparing low stress or stress free coatings and articles utilizing the electrodeposition methods described herein, may be used in conjunction with other methods of preparing low stress or stress free coatings and articles. Such methods include the use of chemical deposition such as electroless (auto-catalytic) deposition or plating, chemical vapor deposition, or physical vapor deposition. Such processes may be advantageous where it is difficult to electrodeposit specific metals such as aluminum, titanium, and magnesium.
EXAMPLES
The following examples are merely intended to illustrate the practice and advantages of specific embodiments of this disclosure; and are not intended in any way to limit or illustrate any limits of the methods, articles or embodiments described herein. Example 1: Low Stress Electrodeposition of Iron Deposition of iron layers in a low stress or stress free form may be accomplished using an offset sine wave to control current density in the electrodeposition process. The beta value is defined as the ratio of peak cathodic to peak anodic current densities; alternately, (3A is defined as the ratio cathodic charge density (integral of the cathodic portion of j(t) with respect to time) to the anodic charge density (integral of the anodic portion of j (t) with respect to time). At low beta value (< 1.8), the electroplated iron layers have low hardness and high ductility. The electroplating system includes a tank, electrolyte of FeCl2 bath with or without CaC12, computer controlled heater to maintain bath temperature, a power supply, and a controlling computer. The anode is low carbon steel sheet, and cathode is titanium plate which will make it easy for the deposit to be peeled off. Carbon steel can also be used as the cathode if the deposit does not need to be peeled off from the substrate. Polypropylene balls are used to cover the bath surface in order to reduce bath evaporation. The process for producing an iron laminate is as follows: 1. Prepare a tank of electrolyte consisting of 2.0 M FeCl2 plus 1.7 CaC12 M in deionized water. 2. Adjust the pH of the electrolyte to -0.5 - 1.5 by addition of HCI. 3. Control the bath temperature at 60 C.
[0004] Clean the titanium substrate cathode and low carbon steel sheet anode with deionized water and immerse both of them into the bath. 5. To start electroplating a high ductility layer, turn on the power supply, and controlling the power supply to generate a shifted sine wave with a beta of 1.26 ((3A = 1.50) by setting the following parameters: 250 Hz with a peak cathodic current density of 43 mA/cm2, and a peak anodic current density of -34 mA/cm2 applied to the substrate (i.e., a peak to peak current of 78 mA/cm2 with a DC offset of 4.4 mA/cm2). Continue electroplating for an amount of time necessary to achieve the desired high ductility layer thickness. 6. Remove the substrate and deposit from the bath and immerse in DI water for minutes and blow it dry with compressed air. 7. Peel the deposit from the underlying titanium substrate to yield a free- standing low stress iron sheet. Example 2: Electrodeposition of Low Stress High Elongation Nickel-Iron Alloy Low stress or stress free Ni-Fe alloys can be electrodeposited using a shifted sine wave with a defined 0 value (see Figure 2 and associated text). At low beta values (< 1.3), the electroplated iron-nickel alloy layers have low hardness, low stress, larger grain size, and high elongation, while at high beta (> 1.5), the plated iron-nickel alloy layers have higher hardness, smaller grain size and lower elongation. At beta value of (<1.25), the deposited Ni- Fe alloy film's stress is almost zero, which makes it possible to obtain low stress and ductile Ni-Fe alloy deposits without sulfur co-deposition caused by adding stress reducing additives such as saccharin. The low stress Fe-Ni deposit makes it possible to deposit very thick layers. It is also possible to deposit onto semiconductors and low adhesion substrates such as conductively coated non-conductive mandrels.
Because no sulfur containing additives are used, it is possible for these Ni-Fe alloy deposits to be used at high temperature environments without brittleness caused by co-deposited sulfur. For electrodeposition of Ni-Fe alloys the system includes a tank, an electrolyte of a mixture of FeCl2 and NiC12, a computer controlled heater to maintain bath temperature, a power supply, and a controlling computer. The anode is an Ni-Fe alloy plate. Any conductive material can be used as the cathode, however, where titanium is used as the cathode, the deposit can be removed from its surface. Carbon steel can be used as the cathode if the deposit does not need to be removed from the substrate. Polypropylene balls are used to cover the bath surface in order to reduce bath evaporation. Electrodeposition of the Ni-Fe laminate is conducted as follows:
1. A tank (bath) of electrolyte consisting of a mixture of 1.0 M FeC12 and 1.0 M NiC12 in deionized water is prepared.
2. The pH of the electrolyte is adjusted to 0.8 by addition of HCI.
3. The bath temperature is maintained at 50 C.
4. The substrate cathode (metals, alloys, semiconductors, or conductively coated non- conductive mandrels) and the Fe-Ni alloy anode are cleaned with deionized water and immersed in the electrolyte bath.
5. Electroplating of a low stress, high ductility layer is started by providing power to the electroplating power supply, and controlling the power supply to generate a shifted sine wave with a 0 value of 1.25 by setting the following parameters: 250 Hz with a peak-to - peak current density of 60 mA/cm2, a DC offset current density 3.3 mA/cm2. Electroplating is continued for an amount of time necessary to achieve the desired thickness.
6. The substrate bearing the electrodeposited Fe-Ni alloy is removed from the bath and immerse in deionized water for 10 minutes and blown dry with compressed air.
7. The electrodeposited Ni-Fe alloy is removed by peeling it from the underlying substrate to yield a free-standing nickel-iron film. Alternatively, the deposited nickel-iron alloy may be left as a deposit on the substrate.
Example 3:
Electrodeposition of low stress Ni films using Shifted Sine Wave Electrodeposition of nickel films may be accomplished using a shifted sine wave similar to that employed in Example 2. At low beta values (< 1.3) electroplated nickel films have low hardness, low stress, larger grain size, and high elongation, while at high beta (> 1.5), the plated nickel films have higher hardness, smaller grain size and lower elongation. At beta value of (<1.25), deposited Ni films have almost zero stress, which makes it possible to obtain low stress and ductile Ni deposits without sulfur co-deposition from stress reducing additives such as saccharin. The low stress of Ni deposit electrodeposited using the embodiments disclosed herein makes it possible to deposit very thick layers. By controlling the wave form used to deposit nickel in a low stress or stress free format, it is also possible to electrodeposite nickel onto low adhesion substrates such as conductively coated non- conductive mandrels. Because no sulfur containing additives are used, it is possible for these Ni deposits to be used in high temperature environments without becoming brittle due to co- deposited sulfur. For electrodeposition of nickel the system includes a tank, an electrolyte of NiC12, a computer controlled heater to maintain bath temperature, a power supply, and a controlling 17 computer. The anode is a nickel plate. Any conductive material can be used as the cathode. However, where titanium is used as the cathode, the deposit can be removed from its surface. Carbon steel can be used as the cathode if the deposit does not need to be removed from the substrate. Polypropylene balls are used to cover the bath surface in order to reduce bath evaporation. The process for producing an iron deposit is as follows:
1. A tank (bath) of electrolyte consisting of a mixture of 1.0 M NiC12 in deionized water is prepared.
2. The pH of the electrolyte is adjusted to 0.8 by addition of HC1.
3. The bath temperature is maintained at 50 C.
4. The substrate cathode (metals, alloys, semiconductors, or conductively coated non- conductive mandrels) and the nickel anode are cleaned with deionized water and immersed in the electrolyte bath.
5. Electroplating of a low stress, high ductility layer is started by providing power to the electroplating power supply, and controlling the power supply to generate a shifted sine wave with a 0 value of 1.25 by setting the following parameters: 250 Hz with a peak-to - peak current density of 60 mA/cm2, a DC offset current density 3.3 mA/cm2. Electroplating is continued for an amount of time necessary to achieve the desired thickness.
6. The substrate bearing the electrodeposited nickel is removed from the bath and immersed in deionized water for 10 minutes and blown dry with compressed air
7. The electrodeposited nickel is removed by peeling it from the underlying substrate to yield a free-standing nickel film. Alternatively, the deposited nickel may be left as a deposit on the substrate.
Composite Armor Material and Method of
Manufacture
US2009217812
US2009217812
An armor material and method of manufacturing utilize nano- and/or microlaminate materials. In one embodiment, the armor material comprises a layered composite material including a strike face, a core layer, and a spall liner. The strike face achieves hardness and toughness by the controlled placement of hard and tough constituent materials through the use of nano- and/or microlaminate materials. The core layer achieves energy absorption through the use of nano- or microlaminated coated compliant materials. The spall liner provides reinforcement through the use of nano- or microlaminated fiber reinforced panels. In one embodiment, nano- and/or microlaminated materials can be manufactured through the use of electrodeposition techniques.
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. (U.S.S.N.) 60/992,877, entitled “Composite Armor Material and Method of Manufacture”, filed on Dec. 6, 2007. The entire disclosure of U.S. Ser. No. 60/992,877 is incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0002] This disclosure relates to composite armor materials and methods of manufacturing such a materials. Armor produced using the disclosed methods and composite armor materials can include one or more of the following advantages: a) an outer layer or strike face providing excellent hardness and toughness b) a middle or core layer that absorbs substantial compressive energy and substantially impedes pressure waves associated with ballistic impact, and c) an inner layer (i.e., a spall liner) having improved reinforcement to prevent ballistic penetration. Additional advantages afforded by the claimed material include resistance to chemical attack, a high strength-to-weight ratio, and easy production of a multitude of armor geometries.
BACKGROUND
[0003] Armor has been used throughout history as protective clothing or outer layer intended to prevent harm from projectiles. Today's advanced armor is a layered composite material. In general, modern composite armor includes three layers: (1) an outer region also known as a strike face that is intended to blunt and disrupt the impact of an incoming projectile and to distribute the resulting force, (2) a middle or core region designed to absorb energy and attenuate pressure waves, and (3) an inner region known as a spall liner to minimize and/or prevent complete penetration of the projectile or blast by-products.
SUMMARY OF THE DISCLOSURE
[0004] The present disclosure applies to materials used in armor (e.g., armored clothing/fabric, armored vehicles) and methods of manufacturing such materials. By employing deposition (e.g. electrodeposition) of laminate materials (e.g., nanolaminate materials, microlaminate materials), greater strength-to-weight ratios can be achieved as compared with conventional armor. In addition, the strike face of the disclosed material has excellent hardness and toughness, the core region can absorb substantial compressive energy and attenuate pressure waves, while the spall liner provides reinforcement to prevent ballistic or blast by-product penetration as compared to conventional armor. Methods described herein (e.g., electrodeposition) provide advantages including the ability to produce a multitude of armor geometries and the ability to create a cohesive layered material, i.e., a well-bonded layered material whose layers/regions work together to minimize damage from an impacting projectile.
[0005] One aspect of the present disclosure is to provide a layered material that minimizes damage caused by an impacting projectile. The layered material includes a strike face region that blunts and disrupts the impacting projectile and distributes the force of impact over a comparatively large area; a core region designed to absorb energy from an impacting projectile and attenuate blast-induced pressure waves; and a spall liner region adapted to prevent penetration by-products of the impacting projectile. The strike face can include a compositionally or structurally modulated nanolaminate material that modulates between hard and tough constituent materials or phases. The core region can include a nano- or microlaminate material that reinforces a compliant phase material such as, for example, a polymer or foam. The spall liner can include a nano- or microlaminate reinforced long-range periodic material, such as fibrous material.
[0006] In another aspect, embodiments described in the present disclosure are directed to composite armor material comprising a plurality of layers, wherein the plurality of layers comprises an electrodeposited modulated material including a modulation wavelength less than about 1000 microns. Such embodiments can include one or more of the following features. The composite armor material may comprise a porous substrate including an accessible interior void structure at least partially filled with the electrodeposited modulated material. The composite armor material may be compositionally modulated. In some embodiments, the composite armor material may be structurally modulated.
[0007] Embodiments of this aspect of the disclosure can also include one or more of the following features. In some embodiments, the composite armor material can have a plurality of layers arranged to define a strike face region, a core region, and a spall liner region, where the strike face region provides toughness and hardness to distribute force of an impacting projectile, and the core region provides energy absorption to absorb energy from the impacting projectile, and the spall region provides strength to inhibit penetration of the armor material. The strike face region may comprise a periodic hard-tough transitions, wherein the periodic hard-tough transitions may be graded. In some embodiments, the strike face region comprises a laminated material. In some embodiments, the core region comprises a metal phase and a compliant phase, wherein the metal phase may comprise a laminated material, and the compliant phase may include a porous template, in which void regions of the porous template may be filled by a gas or liquid. In some embodiments, the compliant phase may include a low density solid, such as a polymer or a foam having a density of less than about 5 g/cc. In some embodiments, the spall liner region of the composite armor material may comprise fibers and a laminated material, wherein the fibers may be reinforced with a sheath formed of the laminated material, and the fibers may be disposed within a matrix of the laminated material. In other embodiments, the boundaries between regions of the plurality of layers in the composite armor material are graded.
[0008] Another aspect of this disclosure is to provide a method for the manufacture of a composite armor material, wherein one or more of the regions within the material is produced through electrodeposition. For example, at least one of the strike face region, core region, and spall liner region is made using electrodeposition of nanolaminate or microlaminate materials.
[0009] In another aspect, embodiments described herein are directed to methods of producing a composite armor material. The methods includes providing an electrolyte containing a metal; providing a porous substrate; immersing the porous substrate in the electrolyte; passing an electric current through the porous substrate so as to deposit the metal onto the porous substrate; and changing one or more plating parameters in predetermined durations between a first value, which is known to produce a material with one property, and a second value, known to produce a material with a second property, to form a portion of at least one of a strike face region, a core region, and a spall liner region.
[0010] Embodiments of the above methods can also include one or more of the following features. The plating parameter of the method can include one or more of pH set point value of the electrolyte bath, electrolyte composition of the bath, applied plating current, applied plating voltage, and mass transfer rate. The plating parameter can be change, in some embodiments, according to one of a square wave, a triangle wave, and a sine wave.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure.
[0012] FIG. 1 is an illustration of a cross-sectional view of an electrodeposited armor.
[0013] FIG. 2 is a an illustration of a cross-sectional view of a strike face region of the electrodeposited armor of FIG. 1.
[0014] FIG. 3A is a graph showing a waveform of iron content in a nickel-iron compositionally modulated electrodeposited material and FIG. 3B is a corresponding composition map.
[0015] FIG. 4 is an illustration of several embodiments of a porous template.
[0016] FIG. 5a is a scanning electronmicrograph (SEM) image of a liquid nitrogen-chilled fracture surface of a metal nanolaminate deposited over a reticulated foam substrate at a magnification of 24×. FIG. 5b is a SEM image of the same fracture surface at a magnification of 100×. FIG. 5c is a SEM image of the same fracture surface at a magnification of 600×.
[0017] FIG. 6 is an illustration of a cross-sectional view of a composite material utilized within a spall liner region of the composite armor of FIG. 1.
[0018] FIG. 7 is an illustration of a cross-sectional view of another composite material utilized within the spall liner region of the composite armor of FIG. 1.
[0019] FIG. 8 is an illustration of a cross-sectional view of an embodiment of an electrodeposited compositionally modulated material.
[0020] FIG. 9a is an illustration of a cross-sectional view of a porous substrate formed from a carbon fiber tow reinforced with an electrodeposited nanolaminated metal. FIGS. 9b and 9c are illustrations of another porous substrate reinforced with electrodeposited metal. Specifically, FIG. 9b is an illustration of a reticulated foam including 6 struts and FIG. 9c is a cross-sectional view of one of the struts showing the nanolaminated metal reinforcing the strut (substrate).
[0021] FIG. 10 is an illustration of a cross-sectional view of a composite material. This composite material includes a consolidated porous substrate with a compositionally modulated electrodeposited material filling at least a portion of an open, accessible void structure of the porous substrate.
[0022] FIG. 11 is an illustration of a cross-sectional view of the compositionally modulated material of FIG. 10 along one of the voids.
[0023] FIG. 12 is an illustration of an electroplating cell including a working electrode attached to a porous substrate.
[0024] FIGS. 13a, 13b, 13c, 13d, 13e are graphs showing electrodeposition conditions and resulting compositional maps for the deposition conditions. FIG. 13a is a plot of applied frequency to a working electrode in an electrochemical cell versus time. FIG. 13b is a plot of applied amplitude to a working electrode in the electrochemical cell versus time. FIG. 13c is a plot of applied current density to a working electrode in the electrochemical cell versus time. FIG. 13d is an envisioned resulting deposit compositional map corresponding to the applied current density given in FIG. 13c, that is for one frequency modulation cycle. FIG. 13d is an envisioned compositional map corresponding to application of ten frequency modulation cycles of deposition.
[0025] FIGS. 14a-14c are illustrations of cross-sectional views of various embodiments of composite materials. FIG. 14a is an illustration of a composite including an electrochemically infused particle bed having a particle distribution that gradually increases from the exterior surfaces of the composite into the center of the composite. FIGS. 14b and 14c are other illustrations of a composite including an electrochemically infused particle bed. In FIG. 14b, the particles have a repeating size distribution. In FIG. 14c the particles have a graded size distribution.
[0026] FIGS. 15a and 15b are illustrations of two separate embodiments of a compositionally modulated material disposed within the void structure of four particles.
[0027] FIG. 16 is an illustration of a cross-sectional view of an embodiment of a composite material including a nanostructured capping layer deposited on an exterior surface of a porous substrate.
[0028] FIG. 17 is an illustration of a cross-sectional view of an embodiment of a consolidated, conductive porous substrate with a tailored filling of a compositionally modulated electrodeposited coating disposed within its accessible void structure. Deposition conditions for this embodiment have been tailored to not only vary a thickness of the coating throughout the depth of the consolidated conductive porous substrate, but also to cap or seal the composite with a dense compositionally modulated layer that closes off accessibility to the interior void structure.
[0029] FIG. 18 is an illustration of a flow cell for electrodepositing a compositionally modulated material into a void structure of an electrically conductive porous substrate.
[0030] FIG. 19 is an illustration of a flow cell for electrodepositing a compositionally modulated material into a void structure of an electrically non-conductive porous substrate.
DETAILED DESCRIPTION
[0031] Referring to the drawings, FIG. 1 illustrates one embodiment of an electrodeposited composite armor comprising 1) a hard strike face intended to a) blunt and disrupt impacting projectiles and b) distribute the force of impact over a comparatively large area; 2) an energy absorbing core designed to a) absorb additional energy from the impacting projectile and b) attenuate blast-induced pressure waves; and 3) a spall liner designed to prevent complete penetration by products of the impact event. One or more additional regions can be added to the embodiment of FIG. 1.
[0032] Features of the strike face (1) include both superior hardness and toughness, which can be achieved by the controlled placement of hard and tough constituent materials within the strike face volume. Periodic hard-tough transitions can serve to arrest crack growth and improve fracture toughness.
[0033] Referring to FIG. 2, the strike face, for example, may consist of a thick compositionally or structurally modulated material (4) with a modulation wavelength (5) varying between 1 and 1000 nm. The local hardness within the deposit can be controlled through the modulation wavelength, the grain size, and/or the composition/phase. Above a certain minimum, typically 2-20 nm, smaller modulation wavelengths produce stronger, harder deposits through Hall-Petch strengthening. Below this wavelength cutoff (e.g., less than about 2-20 nm), hardness and strength decrease with decreasing wavelength. Wavelength modulations therefore can impart modulations in the local hardness of the laminate. For example, it is believed that as the wavelength decreases from 1000 nm towards ~2-20 nm, hardness and strength increases; once below the 2-20 nm range, it is believed that the strength and hardness begin to decrease. The same approach holds true with structurally modulated materials, such as materials that are modulated in grain size or phase. For example, in embodiments where the grain size is modulated, hardness peaks at a grain size of approximately 2-20 nm. For example, in alloy systems which exhibit phase transitions such as fcc?bcc at a given alloy composition, a comparatively ductile fcc alloy can be interposed between strong and hard bcc material to form the structurally (phase) modulated material. The strike face may also contain ceramic particles such as boron carbide, silicon carbide, silicon nitride, or alumina embedded within the electrodeposited metal matrix, which may itself be a compositionally modulated alloy as described above. Modulating the concentration of ceramic inclusions would provide additional hardness modulation, and would additionally function to abrade impacting projectiles (6). Hard regions (7) may therefore be characterized by of one or more of the following: 1-20 nm grains, 2-20 nm wavelengths, bcc phases, and ceramic particle-rich regions, while tough regions (8) include one or more of the following >20 nm grains or wavelengths, <2 nm grains or wavelengths, regions of low/no ceramic inclusions, and fcc phases. In all of the cases described above, an additional embodiment may include gradation of the transition between hard and tough regions, such that the interface is blurred and delamination impaired as shown in FIG. 3.
[0034] In some embodiments, such as illustrated in FIG. 4, strike faces may be produced by electrodepositing a tough metal phase (9) through one or more hard ceramic templates (10; i.e., a substrate, a porous substrate) including, for example, perforated ceramic plates (10a) and/or arrays of ceramic tiles (10b). The metal phase may itself be nano- and/or micro-laminated. The ceramic template may be modified, either by surface functionalization or roughening, to optimize the adhesion between itself and the metal.
[0035] The energy-absorbing material of the core layer (2) includes a minor volume fraction (<50%, e.g., 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%) metal phase reinforcing and/or binding an otherwise soft/compliant phase, which may include gases, liquids, or solids such as polymers or low density solids (e.g., <5 g/cc). An example of such a core material is a reticulated foam reinforced with a metal nano-/microlaminate coating (11) as shown in FIGS. 5a, 5b, and 5c. Another embodiment may include polymeric or foam templates (porous templates), analogous to the ceramic templates described above in FIG. 4 (10a, b), which have been infiltrated with nano- or micro-laminated metal having the structures described in the paragraphs accompanying FIG. 2 above. The common feature of these core designs is their substantial compressive energy absorption and their impedance to pressure waves induced by blasts. Thus, a core region material has a compliant phase (e.g., a foam, or other porous material, which can include a compliant solid such as a polymer) having a form which absorbs energy (e.g., a foam, a bed of beads filled with a liquid or gas.) The core region also includes a metal phase that reinforces and or binds (e.g. encapsulates bed of beads, nanolaminate coating on exterior of foam) the compliant phase.
[0036] The spall liner (3) component of the composite armor design comprises a strong reinforcing material with long range periodicity such as woven carbon fiber, woven S2 glass, or woven Kevlar. A representative block of spall liner material is shown as (12) in FIG. 6 below. FIG. 6 illustrates in cross-section a woven fibrous composite panel with a polymer matrix (14) for a single tow of reinforcing fiber (13). The exterior of this fibrous panel has been further reinforced with a nano-/microlaminated metal coating (15). In a variant (16) of the previous embodiment shown as FIG. 7, the fibers themselves may be reinforced with a thin nanolaminated metal sheath (17) prior to polymer infusion. A further embodiment replaces the polymer matrix entirely with a nanolaminated metal, infused through a non-conductive woven fiber material (e.g. S2 glass, Kevlar) or conformally plated onto a conductive fiber material (e.g. graphite, metalized S2 glass, or metalized Kevlar).
[0037] The nano- and/or microlaminated materials included in the strike face, core layer, and/or the spall liner can be produced by electrodeposition (electroplating) under controlled, time-varying conditions. These conditions include one or more of the following: applied current, applied voltage, rate of agitation, and concentration of one or more of the species within the electroplating bath (e.g., a bath including one or more of an electrodepositable species such as nickel, iron, copper, cobalt, gold, silver, zinc, or platinum). Nano- or microlaminations are defined here as spatial modulations, in the growth direction of the electrodeposited material, in structure (e.g. grain size, crystallographic orientation, phase), composition (e.g. alloy composition), or both. Nanolaminates include a modulation wavelength that is less than 1 micron—i.e., the modulation wavelength is nanoscale. (See International Patent Publication No. WO2007021980 for a further description of nanolaminate materials and electrodeposition of nanolaminate materials; WO2007021980 is herein incorporated by reference in its entirety.) Microlaminates include a modulation wavelength that is less than 1000 microns. Metal nano- or microlaminates can be applied over a variety of substrates (e.g., preforms). In some embodiments the substrate includes a porous preform such as a honeycomb, fiber cloth or batting (woven or nonwoven), a reticulated foam (see FIGS. 5a, 5b, 5c and 9b and 9c), or a tow of fibers (see FIG. 9a), most of which possess little structural integrity in their original form, and can therefore be shaped to the desired component geometry prior to electrodeposition. In addition, metal nano- or microlaminates can be deposited throughout a porous preform formed of an unconsolidated material (e.g., a bed of powder or beads) or through a porous preform created by perforated ceramic plates or tiles. Metal laminates can be deposited into the open, accessible interior void structure of a porous preform, as well as on an exterior surface of any preform (solid substrate or porous preform). Furthermore, plating conditions (i.e. parameters) can be controlled to effect both uniform nano- or microlaminate growth throughout the preform, as well as preferential growth and densification near the external surface of the porous preform. That is, deposition of the nano- or microlaminate material can be controlled such that the laminate's thickness increases throughout the porous preform (or at least a portion of the preform). In this fashion, all three layers (1, 2, and 3) of the armor can be produced in a single production run without removing the part from the plating tank.
Methods and Materials
[0038] In some embodiments, nano- and/or microlaminated materials included within the strike face, the core layer, and/or the spall liner can include compositionally or structurally modulated materials. The compositionally modulated or structurally modulated materials can be formed through the use of electrodeposition. Some exemplary electrodeposition techniques and materials are provided within this section entitled “Methods and Materials.” These techniques and materials are not meant to be exhaustive, but rather are merely illustrative of possible embodiments of the technology disclosed herein.
[0039] The term “compositionally modulated” describes a material in which the chemical composition varies throughout at least one spatial coordinate, such as, for example, the material's depth. For example, in an electrochemical bath including a nickel-containing solution and an iron-containing solution, the resulting compositionally modulated electrodeposited material 20 (FIG. 8) includes alloys having a chemical make-up according to NixFe1-x, where x is a function of applied current or voltage and mass transfer coefficient at the deposition surface. Thus, by controlling or modulating at least one of the mass flow of the bath solution or the applied current or voltage to electrodes, the chemical make-up of a deposited layer can be controlled and varied through its depth (i.e., growth direction). As a result, a compositionally modulated electrodeposited material, as illustrated by material 20 shown in FIG. 8, may include several different alloys as illustrated by layers 30, 32, 34, 36, and 38.
[0040] A “structurally modulated material” is similar to a compositionally modulated material, except that in a structurally modulated material the structure (e.g., grain size, phase, crystallographic orientation, etc.) is modulated rather than the composition. The remainder of this section will describe compositionally modulated materials. However, the same techniques can be used to create structurally modulated materials as well. For example, electrodeposition variables such as the flow rate which affects the deposition rate can be manipulated to grow the deposited material with a finer or larger grain size. Similarly, the growth rate and constituents of the deposited material can be manipulated to control the phase of the electrodeposited material.
[0041] Referring to FIG. 8, layers 32 and 36 represent nickel-rich (x>0.5) deposits in a compositionally modulated laminate material, whereas layers 30, 34, and 38 represent iron-rich (x<0.5) deposits. While layers 32 and 36 are both nickel rich deposits, the value for x in each of layers 32 and 36 need not be the same. For example, the x value in layer 32 may be 0.7 whereas the x value in layer 36 may be 0.6. Likewise, the x values in layers 30, 34, and 38 can also vary or remain constant. In addition to the composition of the constituents (e.g., Ni and Fe) varying through the depth of the electrodeposited material 20, a thickness of each of the layers 30 to 38 varies through the depth as well. FIG. 8, while not to scale, illustrates the change or modulation in thickness that can be made through the layers 30, 32, 34, 36, and 38.
[0042] FIGS. 10 and 11 illustrate a different embodiment of a composite material 18 (e.g., a material included in one or more of layers 1, 2, or 3 of the armor in FIG. 1). In this embodiment, a porous substrate 19 is a consolidated porous body. That is, the porous substrate 19 in this embodiment is a unitary piece that includes a plurality of voids 25 that define an accessible, interior void structure. Examples of consolidated porous bodies include, foams, fabrics, meshes, fibrous panels, ceramic plates, ceramic titles, and partially sintered compacts. The compositionally modulated material 20 (a different embodiment than shown in FIG. 8) is electrodeposited throughout the accessible, interior void structure to form a coating along the walls of the porous substrate 19 defining the voids 25.
[0043] Referring to FIG. 11, the compositionally modulated material 20 disposed within the plurality of voids 25 (as shown in FIG. 10) includes multiple alloys illustrated as distinct layers 31, 33, 35, and 37. As described above, the compositionally modulated material 20 is varied in both constituent concentration (i.e., to form the different alloy layers making up the material 20) and in thickness of the layers. In the embodiment shown in FIG. 11, nickel-rich layers 33 and 37 further include a concentration of particles disposed therein, thereby forming particle-reinforced composite layers. As shown in FIG. 11, layers 33 and 37 need not include the same concentration of particles, thereby allowing the compositionally modulated material 20 to be further tailored to provide optimal material properties. While not wishing to be bound by any particular theory, it is believed that increasing the concentration of the particles in a layer increases the hardness of that particular layer. The concentration of particles per layer can be controlled through modulating the flow rate of the bath during electrodeposition. The particles can have any shape, such as spherical particles, pyramidal particles, rectangular particles, or irregularly shaped particles. In addition, the particles can be of any length scale, such as for example, millimeter sized (e.g., 1 to 5 millimeter), micron-sized (e.g., 100 microns to 0.1 microns), nanometer sized (e.g., 100 nm to 1 nm). In some embodiments, 85% or more (e.g., 87%, 89%, 90%, 93%, 95%, 96%, 97%, 98%, 99%, 100%) of the nanosized particles have an average grain size within a range of 10 nm to 100 nm. In certain embodiments, 85% or more of the nanosized particles have an average grain size within a range of 20 nm to 50 nm, 30 nm to 50 nm, 10 nm to 30 nm, or 1 to 10 nm. Examples of some suitable particles include carbide particles, alumina particles, glass particles, polymer particles, silicon carbide fibers, and clay platelets.
[0044] To form or deposit the compositionally modulated electrodeposited material 20, the porous substrate 19 can be submerged into an electrochemical cell. Referring to FIG. 12, an electrodeposition cell 50, in one embodiment, includes a bath 55 of two or more of metal salts, a cathode (i.e., working electrode) 60, an anode (i.e., a counter electrode) 65, and a power supply (e.g. a potentiostat) 70, which electrically connects and controls the applied current between the working and counter electrodes, 60 and 65, respectively. The cell 50 can also include a reference electrode 75 to control the potential of the substrate relative to a fixed, known reference potential. In general, when an electrical current is passed through the cell 50, an oxidation/reduction reaction involving the metal ions in the bath 55 occurs and the resulting product is deposited on the working electrode 60. As shown in FIG. 12, the porous substrate 19 is positioned in contact with the working electrode 60. For example, in certain embodiments, the porous substrate is formed of a conductive material and functions as an extension of the working electrode 60. As a result, the resulting product of the oxidation/reduction reaction deposits within the accessible interior void structure. In other embodiments, the porous substrate 19 is formed of a nonconductive material and thus, electrodeposition occurs at a junction between the working electrode 60 and the porous substrate 19.
[0045] In general, one of the advantages of the methods and resulting composite materials described in this disclosure is a wide range of choices of materials available for deposition into the interior void structure 25 of the porous preform 19 or on the exterior of a porous or solid preform. For example, salts of any transition metal can be used to form the bath 55. Specifically, some preferred materials include salts of the following metals: nickel, iron, copper, cobalt, gold, silver, zinc, and platinum. In addition to the wide range of materials available, electrodeposition techniques have an additional advantage of easily modifiable processing conditions. For example, a ratio of the metal salts and other electrodepositable components, such as, for example, alumina particles, can be controlled by their concentration within the bath. Thus, it is possible to provide a bath that has a Ni:Fe ratio of 1:1, 2:1, 3:1, 5:1, 10:1 or 20:1 by increasing or decreasing the concentration of a Fe salt within the bath in comparison to the Ni salt prior to deposition. Such ratios can thus be achieved for any of the electrodepositable components. Where more than two electrodepositable components are provided, such ratios can be achieved as between any two of the components such that the overall ratios for all components will be that which is desired. For example, a bath with Ni, Fe and Cu salts could yield ratios of Ni:Fe of 1:2 and a Ni:Cu of 1:3, making the overall ratio of Ni:Fe:Cu 1:2:3. In addition, a bath with Ni salt and alumina particles could yield a ratio of Ni:Al2O3 of 2:1, 2:1, 1:2, 3:1 or 1:3 by increasing or decreasing the concentration of particles within the bath.
[0046] FIGS. 13A, 13B, and 13C illustrate applied conditions to an electrochemical cell, such as that illustrated as 50 in FIG. 12, for depositing the compositionally modulated material 20. FIG. 13D illustrates a resulting composition map for the applied conditions shown in FIGS. 13A, 13B, and 13C. FIG. 13C shows the current density over a period of 130 seconds applied to a working electrode (e.g., working electrode 60 in FIG. 12). The applied current drives the oxidation/reduction reaction at the electrode to deposit a material product having the form AxB1-x, where A is a first bath constituent and B is a second bath constituent. While FIG. 13C illustrates a current density range of between -20 to -100 mA/cm<2>, other current density ranges are also possible for example, a current density range of between about -5 to -20 mA/cm<2 >may be advantageous in some embodiments.
[0047] Another way of tailoring the modulation of the compositions of the deposited alloys (AxB1-x, where x varies) is with respect to a composition cycle. Referring to FIG. 13D, a composition cycle 80 defines the deposition of a pair of layers. The first layer of the composition cycles is A-rich and the second layer is B-rich. Each composition cycle has a wavelength. A value assigned to the wavelength is equal to the thickness of the two layers forming the composition cycle 80. That is, the wavelength has a value that is equal to two times the thickness of one of the two layers forming the composition cycle (e.g., ?=10 nm, when thickness of Ni-rich layer within the composition cycle is equal to 5 nm). By including one or more composition cycles the deposited material is compositionally modulating. In an advantageous embodiment, the compositionally modulated electrodeposited material includes multiple composition cycles (e.g., 5 composition cycles, 10 composition cycles, 20 composition cycles, 50 composition cycles, 100 composition cycles, 1,000 composition cycles, 10,000 composition cycles, 100,000 composition cycles or more).
[0048] The applied current density as shown in FIG. 13C is determined from an applied variation in frequency of the current per time (FIG. 13A) in combination with an applied variation in amplitude of the current per time (FIG. 13B). Referring to FIG. 13A, an applied frequency modulation, shown here as a triangle wave, effects the wavelength of the composition cycles. As shown by comparing FIGS. 13A and 13D, the wavelength of the composition cycles decreases as the frequency increases. While FIG. 13A illustrates this effect with an applied triangle wave, any waveform (i.e., a value that changes with time) may be applied to control or modulate the frequency and thus control or modulate the thickness/wavelengths of the deposited material. Examples of other waveforms that may be applied to tailor the changing thickness/wavelength of each of the deposited layers/composition cycles include sine waves, square waves, sawtooth waves, and any combination of these waveforms. The composition of the deposit (i.e., x value) can also be further modulated by varying the amplitude. FIG. 13B illustrates a sine wave modulation of the applied amplitude of the current applied to the working electrode. By changing the amplitude over time, the value of x varies over time such that not all of the Ni-rich layers have the same composition (nor do all the Fe-rich layers have the same composition). Referring to FIGS. 3A and 3B, in some embodiments, the value of x is modulated within each of the layers, such that the compositionally modulated electrodeposited material is graded to minimize or mask composition discontinuities. As a result of applying one or more of the above deposition conditions, the compositionally modulated electrodeposited material can be tailored to include layers that provide a wide range of material properties and enhancements.
[0049] One such enhancement is an increase in hardness. Without wishing to be bound to any particular theory, it is believed that regions of nanolaminate material (i.e., regions in which all of the composition cycles have a wavelength less than about 200 nm and preferably less than about 80 nm) exhibit a hardness not achievable by the same materials at greater wavelengths. This hardness is believed to arise from an increase in the material's elastic modulus coefficient, and is known as the “supermodulus effect.” In certain embodiments, for example, the composite material 20 of FIG. 11, the compositionally modulated electrodeposited material 20 is deposited to include one or more regions, which provide the composite material 18 with the supermodulus effect. That is, the compositionally modulated electrodeposited material 20 disposed within the void structure 25 of the porous substrate 19 or on an exterior surface of a solid or porous substrate includes one or more regions in which all of the composition cycles include wavelengths less than 200 nm, and preferably less than about 80 nm. In one embodiment, the wavelengths are less than about 70 nm. In another embodiment, the hardness of the composite material 18 is enhanced by including varying concentrations of particles (e.g., Al2O3, SiC, Si3N4) within an electrodeposited metal. For example, by increasing the concentration of Al2O3 particles dispersed within layers of an electrodeposited Ni metal, an increase in Vicker's Hardness from 240 VHN to 440 VHN is achievable.
[0050] In some embodiments, the compositionally modulated electrodeposited material can include regions in which the composition cycles include wavelengths less than 200 nm (and thus which may exhibit the supermodulus effect) and also include regions in which some portion (e.g., at least or about: 1%, 2%, 5%, 7%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 92% 95%, 97%, 99% and 100%) of the composition cycles include wavelengths greater than 200 nm. The portion(s) of the composition cycles that include wavelengths greater than 200 nm could also be represented in ranges. For example, the composition cycles of one or more regions could include a number of wavelengths greater than 200 nm in a range of from 1-2%, 2-5%, 1-5%, 5-7%, 5-10%, 1-10%, 10-20%, 20-30%, 30-40%, 40-50%, 50-60%, 60-70%, 70-80%, 80-90%, 90-92%, 90-95%, 95-97%, 95-99%, 95-100%, 90-100%, 80-100%, etc., with the balance of the composition cycles being less than 200 nm in that region. Without wishing to be bound by any particular theory, it is believed that, as hardness increases, ductility decreases. As a result, in order to provide a composite material that is enhanced to include regions of increased hardness and regions of increased ductility, the compositionally modulated electrodeposited material, in some embodiments, can include one or more regions in which all of the composition cycles have a wavelength of about 200 nm or less including wavelengths less than 1 nanometer, one or more regions in which all of the composition cycles have a wavelength greater than 200 nm, and/or one or more regions in which a portion of the composition cycles have a wavelength of about 200 nm or less and a portion have a wavelength greater than 200 nm. Within each of those portions, the wavelengths also can be adjusted to be of a desired size or range of sizes. Thus, for example, the region(s) having composition cycles of a wavelength of about 200 nm or less can themselves have wavelengths that vary from region to region or even within a region. Thus, is some embodiments, one region may have composition cycles having a wavelength of from 80-150 nm and another region in which the wavelengths are less than 80 nm. In other embodiments, one region could have both composition cycles of from 80-150 nm and less than 80 nm.
[0051] In certain embodiments, the compositionally modulated material can be tailored to minimize (e.g., prevent) delamination of its layers during use. For example, it is believed that when a projectile impacts a conventional laminated material, the resulting stress waves may cause delamination or debonding due to the presence of discontinuities. However, the compositionally modulated electrodeposited materials described herein can include a substantially continuous modulation of both its composition (i.e., x value) and wavelength such that discontinuities are minimized or eliminated, thereby preventing delamination.
[0052] Referring to FIGS. 14A-14C, a different embodiment of a compositionally modulated material 20 is shown. In addition to compositionally modulating the electrodeposited material 20 to form the composite 18, the porous substrate material 19 can also be made of a material that is modulated through its depth. For example, as shown in FIG. 14A, in one embodiment, the porous substrate 19 is formed of particles 22 that gradually increase in size from an exterior 100 of the compact to an interior 110 of the composite 18. The particles in such embodiments can range from, e.g., 5 nm on the exterior 100 to 50 microns in the interior 110, 5 nm on the exterior 100 to 10 microns in the interior 110, 5 nm on the exterior to 1 micron in the interior 110, 10 nm on the exterior 100 to 10 microns in the interior 110, or from 10 nm on the exterior 100 to 1 micron in the interior. The differently sized particles 22 contribute to the material properties of the composite 18. For example, smaller particles have a greater surface area energy per unit volume than larger particles of the same material. As a result, the porous substrate 19 can be tailored to provide additional advantageous material properties to different regions of the composite 18. Referring to FIGS. 15B and 15C, the porous substrate 19 can have other particle arrangements to provide different material properties to the composite 18. For example, in FIG. 15B the particles have a repetitive size distribution and in FIG. 15C the particles have a graded distribution.
[0053] FIGS. 15A and 15B show an enlarged cross-sectional view of the compositionally modulated electrodeposited material 20 disposed between four adjacent particles 22 of a porous substrate 19. In FIG. 16A, the particles 22 forming the porous substrate 19 are non-conductive particles (e.g., alumina particles, glass particles). As a result of their non-conductivity, electrodeposition occurs between two electrodes disposed on either end of the porous substrate 19 and the compositionally modulated electrodeposited material 20 is deposited in a bottom-up fashion. Thus, the compositionally modulated electrodeposited material fills the entire void structure 25 between the four particles. In the embodiment shown in FIG. 15B, the particles 22 are electrically conductive. As a result, electrodeposition can occur within the conductive porous material to produce layers that are initiated at a particle/void interface 120 and grow inwards to fill at least a portion of the interior void structure 25.
[0054] As illustrated in the embodiments of FIG. 16 and FIG. 17, in addition to electrodepositing into a porous preform, the compositionally modulated material 20 can also be deposited on the exterior surfaces 100 of the porous substrate 19 to form a nanolaminate or microlaminate coating. For example, after the accessible interior void structure 25 is at least partially filled in the case of an electrically conductive porous substrate or substantially filled in the case of a non-conductive porous substrate, an additional or capping layer 150 can be deposited onto the substrate to seal off the interior porous structure 25 as shown in FIG. 17.
[0055] In certain embodiments, the filling of the accessible interior void structure 25 is tailored such that the thickness of the compositionally modulating electrodeposited material 20 varies throughout the composite 18. For example, FIG. 17 illustrates a composite material 18 formed of a porous conductive foam 19 and a NixFe1-x compositionally modulated material 20. The thickness of the compositionally modulated material 20 continuously increases (i.e., thickens) from the interior portion 110 of the porous substrate 19 to the exterior 100. To create this thickening, the current density during deposition is continuously increased. In addition to including the compositionally modulated material 20 disposed throughout the void structure 25 of the porous substrate 19, a dense layer of the compositionally modulated material, referred to as the capping layer 150 is further applied to the exterior 100 of the substrate 19 to close off the accessible pore structure 25.
[0056] Methods of forming the composite 18 using electrodeposition can include the following steps: (1) forming a bath including at least two electrodepositable components, (2) connecting a preform, such as, for example the porous perform 19, to the working electrode 60, (3) inserting the preform, the working electrode 60, and the counter electrode 65 into the bath 55, and (4) applying a voltage or current to the working electrode 60 to drive electrodeposition.
[0057] In general, in one embodiment, the voltage or current applied to the working electrode 60 varies over time so that the compositionally modulated material is electrodeposited into the voids 25 of the porous preform 19. Thus, in some embodiments, the voltage or current is applied to the electrode 60 with a time varying frequency that oscillates in accordance with a triangle wave. In other embodiments, the voltage or current is applied to the electrode with a time varying frequency that oscillates in accordance with a sine wave, a square wave, a saw-tooth wave, or any other waveform, such as a combination of the foregoing waveforms. The voltage or current can be applied for one waveform cycle as shown in FIG. 13A, or preferably for two or more cycles (e.g., three cycles, five cycles, 10 cycles, 20 cycles). FIG. 13E shows the envisioned composition map for a 10 cycle deposit.
[0058] In addition to controlling the voltage or current, other deposition conditions can also be monitored and varied to tailor the compositionally modulating material 20. For example, it is believed that the pH of the bath has an effect upon the quality of the deposited material. Thus, in some embodiments, the pH of the bath is controlled during electrodeposition. For example, prior to deposition a pH set point (e.g., a pH of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14) or range (e.g., a pH of 1-2, 2-3, 3-4, 5-6, 6-7, 7-8, 8-9, 9-10, 10-11, 11-12, 12-13, or 13-14) is determined. During electrodeposition, the pH of the bath is monitored and if a difference from the set point is determined, pH altering chemicals, such as, for example, HCl, H2SO4, sulfamic acid, or NaOH, are added to the bath to return the bath to its pH set point.
[0059] The concentration of the electrodepositable components in the bath can also be monitored and controlled. For example, concentration sensors can be positioned within the cell 50 to monitor the concentrations of the metal salts as well as any depositable particles within the bath. During electrodeposition of the compositionally modulated material 20, the concentrations of the depositable components (e.g., metal salts, particles) can become depleted or at least decreased from a predetermined optimal level within the bath. As a result, the timeliness of the deposition of the compositionally modulated material 20 can be effected. Thus, by monitoring and replenishing the concentrations of the depositable components electrodeposition can be optimized.
[0060] In certain embodiments, flow rate of the bath can be modulated or varied. As described above, both the applied current or voltage and the mass flow rate of the depositable components effects the x-value of the electrodeposit (e.g., NixFe1-x). Thus, in some embodiments, the flow rate of the bath containing the depositable components is varied in addition to the applied voltage or current to produce the modulation in the value of x. In other embodiments, the applied voltage or current remains constant and the flow rate is varied to produce the modulation in the value of x. The flow rate of the bath can be increased or decreased by providing agitation, such as, for example, a magnetically-controlled mixer or by adding a pump to the cell 50. By agitating the bath or by agitating the preform the mass transfer rate of the electrodeposited material is effected in that electrodepositable species may be more readily available for deposition thereby providing improved deposition conditions.
[0061] FIGS. 18 and 19 illustrate embodiments of an electrochemical cell 50 that includes a pump 200. In general, these cells 50 are referred to as flow cells because they force a bath solution through a porous substrate. Referring to FIG. 18, the flow cell includes a porous working electrode 60, which is also the porous electrically-conductive substrate 19, and a porous counter electrode 65. The working electrode 60, the counter electrode 65 and the reference electrode 75 are in communication and are controlled by the potentiostat 70. The bath fluid 55 including the depositable components is forced through the porous working electrode 60 (and thus the porous substrate 19) and the counter electrode 65 at a flow rate adjustable at the pump 200. Thus, in certain embodiments, the flow rate of the pump 200 can be controlled in accordance with a triangle wave, square wave, sine wave, a saw tooth wave, or any other waveform, such that the flow rate can be modulated to produce the compositionally modulated material 20.
[0062] FIG. 19 illustrates another embodiment of a flow cell 50 for use with non-conductive porous substrates 19. In this cell 50, the working electrode 60 and the counter electrode 65 are disposed within a wall of the cell 50 and the bath fluid 55 is forced through the porous non-conductive substrate 19. Electrodeposition occurs in a bottom-up fashion, that is, the deposition of material 20 proceeds from the working electrode 60 to the counter electrode 65 substantially filling the void structure along the way.
[0063] The methods and composite materials described herein can be tailored to provide the unusual combination of strength, ductility, and low-density. For example, the porous substrate 19 forming the matrix of the composite material 18 can be formed of a light-weight ceramic material or can include a relatively large amount (e.g., 40% by volume, 50% by volume, 60% by volume) of accessible interior void space 25. The compositionally modulated material 20 electrodeposited into the accessible, interior void space 25 can be tailored to provide strength at least in part through nanolaminate regions and ductility at least in part through micron or submicron sized laminated regions.
[0064] In some embodiments, the composite material 18 is deposited on a solid preform (e.g., substrate) and/or a porous preform with closed porosity instead of a porous substrate with open porosity. In these embodiments, the composite material 18 is deposited on the exterior surface of the preform.
[ Machine Translation ]
Material and process for electrochemical
deposition of nanolaminated brass alloys
CN103261479
CN103261479
Described herein are methods of preparing nanolaminated brass coatings and components having desirable and useful properties. Also described are nanolamined brass components and plastic and polymeric substrates coated with nanolaminated brass coatings having desirable and useful properties.
[0001] FIELD
[0002] The present disclosure generally relates to the electrodeposition method, comprising producing brass alloy prepared to exhibit high stiffness and tensile strength of the coating and the cladding of the electrodeposition method is applicable.
[0003] SUMMARY
[0004] Electrodeposition method disclosed in the present embodiment provides a method for forming an article or a coating or cladding, the article or coating or cladding non-toxic, or in combination with toxic materials such as with nickel, chromium and alloys thereof and the like forming a coating or cladding layer is small compared toxicity.
[0005] Other embodiments of the present disclosure provide a method for electrodeposition of high stiffness and high elastic modulus of the deposited layer of brass alloy.
[0006] Other embodiments of the present disclosure provide a plastic or polymeric substrate in the nano-laminate brass coating, the maximum tensile strength of the coating has, flexural modulus, modulus of elasticity and / or stiffness ratio greater than has the maximum tensile strength electrodeposited on the thickness and composition of the nano-coating substantially the same laminated brass uniform brass coating conductive plastic or polymeric substrate, flexural modulus, elastic modulus and / or stiffness ratio.
Other embodiments of the method described for the preparation of those coatings.
[0007] Other embodiments provide a method for electrodeposition on a plastic or polymeric substrate to a thickness of about 100 microns nanocrystalline laminated brass alloy coating.
The coating may be used to enhance a plastic or polymeric substrate.
[0008] Other embodiments provide a brass alloy layer by electrodeposition (coating) a layer formed by the method.
When the brass alloy layer is formed on a mandrel and the mandrel is separated from the brass alloy into the layer or coating may be independent of the mandrel of the article or article component.
[0009] Other embodiments provide products (e.g. member), having a brass alloy by electrodeposition of a layer obtained by coating or cladding layer, comprises depositing on a plastic or polymeric substrate a coating or cladding.
[0010] Other embodiments provide a coating or cladding, which provides a protective barrier in the underlying substrate or object and the outside environment or personnel between the potential for protecting the personnel or the environment from damage caused by the substrate or the object or toxicity.
[0011] Other embodiments provide a coating or cladding, which provides a protective barrier in the underlying substrate or object and the outside environment or personnel between the substrate or object to protect against damage to the external environment, toxicity, freedom from loss and tear or abuse.
[0012] Electrodeposition method can provide at or near ambient temperature embodiment of yet another embodiment of the present disclosure.
The electrodeposition method of making an article, the article comprising nano laminated brass components and / or nano-laminated substrate having a coating of brass, and with the use of the nano-laminate or coating of brass components with the same The maximum tensile strength of the same component even brass alloy composition obtained or coated substrate, compared with higher elastic modulus and / or flexural modulus.
[0013] Brief Description
[0014] Figure 1 shows the comparison with non-coated plastic substrates, plastic substrates for the nano-laminate brass coating, the thickness of the intensity ratio relative to its relevance.
[0015] Figure 2, picture A, is displayed with respect to the uncoated samples of ABS brass coating having a nano-laminate 1/8 inch and 1/16 inch thick ABS (acrylonitrile butadiene styrene) samples observed flexural modulus increased histogram.
Image B shows the flexural modulus with respect to the percentage of the metal nano accounted laminated brass coating sample cross-sectional area occupied by the portion of the scatter plot.
[0016] 3, image A, the display of the nano-laminate coated brass coating thickness of 100 microns thick 1/8, 1/16 and 1/20 inch ABS sample was observed to increase the elastic modulus of the histogram. Growth is displayed with respect to the uncoated sample of ABS.
Figure 3 displays the image B coated ABS sample (with respect to the uncoated sample of ABS) of the elastic modulus increase as the sample is applied to the ABS laminated brass coating cent of the nano-coated ABS sample The cross-sectional area of ??the score function.
Figure 3, image C, the display indicates the cross section nano-laminate coating a polymeric substrate and a position (shown in this case has a rectangular base), thus the calculation of the total cross-sectional area of ??the coating Score (not according to the actual proportions).
[0017] Stiffness ABS samples
Figure 4 shows the ABS with respect to the uncoated sample, a brass coating having a nano-laminate than the growth of the histogram. Shows the nano-laminate brass coating sample cross-sectional area of ??10%, 15% or 20% of the stiffness of the sample growth.
[0018] DETAILED DESCRIPTION
[0019] Electrodeposition to provide a method for forming a thin coating may enhance or protect or cladding in its base beneath the substrate or component, and for forming a coating or cladding parts or components.
It has been found brass electrodeposition coating or cladding provides a satisfactory enhancement and protection of nature and the nature of those species in the electric or electro-deposition of sediment types have electrodeposition microstructure changes periodically nanoscale multilayer further improved when the hierarchy.
Electrodeposition is also provided for forming (e.g., electro-forming) method of an article, the article comprises the mandrel removed from the electrical component or components such as molded and formed on the mandrel.
[0020] As a method, electrodeposition to form a multilayer laminate or a multilayer laminate of "nano-level" (i.e., nano-laminated) articles / components and / or coating provides a number of advantages.
Nano-lamination process to improve the material properties of the base material overall (bulk material) of different compositions by providing alternating layers of nanoscale, thus significantly improve the properties of the material.
And by the composition can be between dissimilar interface added (pinning) the nano-layer to enhance the material by controlling the grain size within each hierarchical.
Cracks or defects arising forced through hundreds or thousands of interface transfer, thereby by blocking dislocation movement so that the material hardens and becomes tough.
[0021] At least a portion disposed in an embodiment of the electrodeposition method, electrodeposition method comprising (a) a mandrel or substrate to be coated in a first electrolyte containing metal ions of zinc and copper and other metals in the desired electrolyte temperature, electrolyte or additive concentration in the electrolyte of stirring one or more layers or in a periodic electric power generating periodic microstructure species sediment deposits species, (b) applying an electric current, and the change with time of the amplitude of the current, layer, (c) extension nano laminated under such conditions (multilayer) coating, and (d) optionally selectively etching the nano-laminate coating until a desired thickness of the nano-laminate coating and finishes.
The method may further comprise (e) removing the mandrel or the substrate from the bath and washing.
[0022] Electrodeposition can be performed on existing conductive plastic or polymer substrates.
In one embodiment, the deposition impart conductivity plastic or polymeric substrate by electroless metal.
Thus, for example, electroless copper plating may be applied to a plastic (such as polyamide plastic substrate) to impart conductivity to the polyamide substrate for subsequent electrodeposition method.
In one embodiment, the electroless copper plating layer may be applied to the 2-3 micron polymer frame.
In other embodiments, any suitable metal may be applied by electroless plating method, including but not limited to electroless nickel plating (see, e.g., U.S. Patent No. 6,800,121), platinum, silver, zinc, or tin to impart a non-conductive substrate ( e.g., plastic or polymer substrates) conductivity.
[0023] In other embodiments, by the conductive material (e.g., graphite) incorporated into the plastic or polymer composition (see, e.g., US4,592,808, on the graphite reinforced epoxy composite material) to make a non-conductive plastic or polymer formation of a substrate having conductivity.
[0024] When necessary or desired, the substrate is a plastic substrate in particular may be roughened to increase the adhesion and / or peel resistance.
By any related methods, including friction surface by sanding or sandblasting to achieve roughening.
Alternatively, a variety of acid or alkali etching surfaces, particularly plastic surfaces.
In addition, ozone etching method can be used (see, for example US4,422,907) or gas-phase sulfonation.
[0025] In one embodiment, the electrodeposition implemented on a plastic or polymeric substrate, the substrate may comprise a plastic or polymeric material in the following one or more of: ABS, ABS / polyamide mixture, ABS / polycarbonate ester mixture, polyamide, polyethyleneimine (polyethyleneimine), polyether ketone, polyether ether ketone, polyaryl ether ketone, epoxy resin, epoxy resin blend, polyethylene, polycarbonate or more thereof.
In one embodiment, the method comprises a copper zinc alloy (brass alloy) layer electrodeposited on the plastic substrate.
The method includes first providing comprising copper and zinc salts of basic electrolyte.
The electrolyte may be electrochemical deposition bath containing cyanides.
Subsequently, provided thereon electrodeposited zinc, conductive polymeric substrate may copper and its alloys, and the at least a portion of the substrate immersed in the electrolyte.
Then varying current through the substrate was immersed portion.
Between the current control effective electrodeposition of a zinc and copper alloy having a specific concentration of the first current and the effective current electrodeposition of zinc and another of the other copper alloy.
You can repeat this changing current, or another current effective electrodeposition of zinc and other copper alloys can be applied.
Changing current thereby producing a multilayer adjacent layers having different alloy brass alloy on a surface of a substrate or dipping the mandrel.
In order to improve the surface finish as well as the relative change in the composition of the alloy surface, can be applied may include a reverse pulse waveform final machining (finishing waveform).
[0026] In another embodiment, the current control can be zinc and copper and a first electrical pulse sequence specific and effective roughness of the alloy electrodeposited on the effective electrodeposition having a specific concentration of the other having a specific roughness of the copper alloy of zinc on the other between a series of electrical pulses.
These different pulses can be repeated sequence to produce a total thickness of greater than 5 microns electrodeposit.
Either electrical pulses of different sequences may include a reverse pulse for reducing the surface roughness, the surface potential reactivation deposits, or to allow the deposition thickness greater than 5 microns and the brass layer has a substantially smooth surface.
[0027] In another embodiment, the multilayer electrodeposited brass components as a product or article (e.g., formed on a mandrel) or a coating method comprising: (a) providing a mandrel or plastic treated with conductive or polymeric substrate; (b) so that the mandrel or at least a portion of the electrolyte contact the conductive plastic or polymeric substrate with a metal comprising zinc and copper ions and optionally other metal ions, wherein the conductive media contact with the anode; and (c) applying a current through the mandrel or a plastic or polymeric substrate and the anode, and change over time: the current amplitude, electrolyte temperature, electrolyte or electrolyte additive concentration in one or more stirred to produce as a coating on the mandrel or on a plastic or polymeric substrate having a desired thickness and kind of periodic electrical sediment layer and / or electrical types of periodic sediment layer of nano-laminate microstructure of the brass coating.
[0028] By applying current or the like in the electrodeposition process to control electrodeposition.
Applying a current can be continuously or according to a predetermined pattern such as waveform.
Specifically, intermittently Shijia Bo-shaped (eg sine, square, ramp, or triangle) to facilitate the electrodeposition process, intermittently reversed electrodeposition process, increase or decrease the deposition rate of change is being deposited composition of the material, and / or provide a combination of such techniques to achieve a particular layer thickness or of different layers in a particular way.
In different layers of the plating process, the current density (or voltage for electroplating) and the waveform cycle can be varied independently, without the need to maintain a constant, but, for the deposition of the different layers may be increased or decreased.
For example, the current density can be continuously or discretely in the range / cm 2 changes between 0.5 and 2000mA.
According to the surface area of ??the substrate to be coated or mandrel, the current density can also vary within other ranges, for example: from about 1 to 20mA / cm 2, from about 5 to 50mA / cm 2, from about 30 to 70mA / cm 2, 1 to 25mA / cm 2, 25 to 50mA / cm 2, 50 to 75mA / cm 2, 75 to 100mA / cm 2, 100 to 150mA / cm 2, 150 to 200mA / cm 2, 200 to 300mA / cm 2, 300 to 400mA / cm 2, 400 to 500mA / cm 2, 500 ? 750 mA / cm 2, 750 to 1000mA / cm 2, 1000 to 1250mA / cm 2, 1250 to 1500mA / cm 2, 1500 to 1750mA / cm 2, 1750 to 2000mA / cm 2, 0.5 to 500mA / cm 2, 100 to 2000mA / cm 2, greater than about 500mA / cm 2, and from about 15 to 40mA / cm 2.
In another embodiment, the frequency of the waveform may be about 0.01Hz to about 50Hz.
In other embodiments, the frequency may be: from about 0.5 to about 10Hz, 0.5 to 10Hz, 10 to 20Hz, 20 to 30Hz, 30 to 40Hz, 40 to 50Hz, 0.02 to about 1Hz, about 2 to 20Hz, or from about 1 to about 5Hz.
In one embodiment, the mandrel is used or a plastic or polymeric substrate nano laminated brass coating method comprising: (i) applying a first cathode current density of about 35 to about 47mA / cm 2 of continuous about 1 to 3sec, then (ii) telogen about 0.1 to about 5 seconds; and repeat (i) within the total time of about 2-20 minutes, and (ii).
After the application of the first cathode current, the method continues to step (iii) is applied from about 5 to 40mA / cm 2 of the second cathode current for about 3 to about 18 seconds, and then (iv) applying from about 75 to about 300mA / cm 2 of The third cathode current period of about 0.2 to about 2 seconds, followed by (v) applying an anode current of about -75 to about -300mA / cm 2 of the period of about 0.1 to about 1 second; and repeating from about 3 to about 9 hours ( iii) to (v).
The method may be repeated to obtain a multilayer nano-laminate brass coating.
For example, by repeating the above steps (i) - (v) performed.
[0029] Also changes over the potential to control the composition of a layer and the layers.
For example, for the potential production of a coating can be in the range of 0.5V to 20V in.
In another embodiment, the potential may be selected from 1V to 20V, 0.50 to 5V, 5 to 10V, 10 to 15V, 15 to 20V, 2 to 3V, 3 to 5V, 4V to 6V, 2.5V to 7.5 V, the range of 0.75 to 5V, 1V to 4V and within 2 to 5V.
[0030] In one embodiment, the coating or cladding, the electrodeposition of a brass alloy having a multi layered nanoscale layer, wherein the electrodeposited species or electrically deposited microstructures varies periodically, and these layers Electrodeposition species or changes in the microstructure of the sediment types electricity provides a high elastic modulus material.
Another embodiment provides an electrodeposition method, the method of forming a laminated brass alloy, wherein the concentration of the layers between the alloying elements is different.
Another embodiment is a brass alloy electrodeposition coating or nano-laminate of the base material, having a microstructure different kinds electrodeposit nanoscale multilayer, and the difference is provided a layer of high elastic modulus material.
[0031] In another embodiment, there is provided a brass alloy having a multi-layer laminated assembly or nano-coating.
The layers have the same or different thickness.
Each layer, referred to herein as nano-layer and / or periodic layer having a thickness of from about 2nm to about 2,000nm of.
[0032] In one embodiment, the brass component comprising nano laminated brass, compared to the nano-laminate is made of brass composed of substantially the same uniform coating of brass alloy is formed having a brass component, showing at least 10% higher, 20% or 30% of the maximum tensile strength.
[0033] In another embodiment, a plastic or polymeric substrate or a portion thereof may be coated with nano-laminated brass coating.
Substrates coated substrate, with or without coating a substrate having a thickness and composition of the nano-laminate of substantially the same brass coating (or the same) of the brass alloy coating uniformity more as compared to strong.
In some embodiments, the maximum tensile strength of the coating of plastic or polymeric substrate with respect to increased uniformly coated plastic or polymeric substrate is greater than 10%, 20% or 30%.
In other embodiments, the maximum tensile strength of the coating of plastic or polymeric substrate with respect to the uncoated plastic or polymeric substrate higher than 100%, 200%, 300%, 400% or 500% .
[0034] In one embodiment, when 5% of the total cross sectional area of ??the nano-coating cross sectional area occupied laminated brass coating a substrate, present in the nano-laminated plastic or polymeric substrate of brass coating, with respect to the plastic or polymeric substrate without said coating, a flexural modulus of greater than 3-fold increase.
In another embodiment, when the nano-laminate brass coating has a 10% cross-sectional area, is present in nano-laminated brass coated plastic or polymer substrate, with respect to the uncoated plastic or polymer substrate, so that an increase of flexural modulus greater than 4 times.
[0035] In other embodiments, the nano-laminate comprising the elastic modulus of brass components is greater than about 60, 65,70,75,80,90,100,110,120,130,140,150,160,180,200, 220,240,250 or 300GPa.
In another embodiment, the nano-laminate brass coating elastic modulus greater than 60,65,70,75,80,90,100,110,120,130,140,150, 160,180,200,220 , 240, 250 or 300GPa.
In another embodiment, the elastic modulus of the nano-assembly or nano-laminate laminated brass brass coating to Gigapascals (GPa) expressed as from about 60 to about 100, or from about 80 to about 120, or about 100 to about 140, or from about 120 to about 140, or from about 130 to about 170, or from about 140 to about 200, or from about 150 to about 225, or from about 175 to about 250, or from about 200 to about 300GPa.
[0036] In one embodiment, the coating of plastic or polymeric substrate so that the stiffness increases.
In such an embodiment, with respect to the uncoated substrate, when about 10% of the cross sectional area of ??nano laminated brass coating coated substrate occupies the total cross-sectional area, nano-laminate stiffness of brass coated plastic or polymeric substrate exhibits exceeds about 2.8-fold increase.
In another embodiment, when about 15% of the cross sectional area of ??the coating base material coating occupies the total cross-sectional area, the observed increase in stiffness than 4 times.
In another embodiment, when about 20% of the cross sectional area of ??the coating base material coating occupies the total cross-sectional area, the observed increase in the stiffness exceeds 7 times.
[0037] The upper surface of at least part of one embodiment, wherein the nano-laminate plastic or brass coating is present in the polymeric substrate, coated with the coating of the article or part of the article exhibits a maximum tensile strength is greater than the uncoated at least 267% of the base.
In another embodiment, the article is a nano-coating of plastic or brass laminated polymer substrate of at least 267%, it exhibits a maximum tensile strength of the nano-laminate having a brass coating substantially the same thickness and composition of the plastic or polymeric substrate brass alloy coating uniformly maximum tensile strength as compared to at least more than 30%.
[0038] When used herein, the thickness of one or more other thicknesses are substantially the same means that one or more of the thickness is 95 to 105% of the other thicknesses.
[0039] As used herein, when (i) a composition comprising nano-laminate in a brass coating composition is greater than 0.05 wt% (i.e., 0.5% by weight of the nano-laminate coating) of all components present, time and (ii) the amount of each component in the composition of its weight in the nanometer laminated brass coating percentage from 95 to 105%, of the composition to the brass-coated nano-laminate layer composition substantially the same.
For example, when the content of a component of the nano-laminate coating by weight of about 2% (with respect to the nano-laminate coating weight and composition of all layers), then (e.g., a uniform coating of the same composition ), the content of the desired fraction by weight of 1.9 to 2.1%.
[0040] Electrodeposition method can be controlled to selectively applied only to some portions of the substrate coating.
For example, brushing or coating techniques can be used administered masking product to cover the base portion, preventing it from being applied in the subsequent electrodeposition process.
[0041] May be at or near ambient temperature (i.e., about 20 ?) ??to a temperature of about 155 ? embodiment embodiment of the method.
Deposited at or near ambient temperature electrical laminate coating allows nano-alloy deposited thereon due to the polymeric substrate or mandrel with the temperature-dependent deformation of the reduced likelihood of defect.
[0042] As used herein, "metal" refers to any metal, metal alloy or other composite material comprises a metal.
In one embodiment, these metals may comprise Ni, Zn, Fe, Cu, Au, Ag, Pt, Pd, Sn, Mn, Co, Pb, Al, Ti, Mg and Cr of one or more.
When deposition of the metal, may be independently selected percentage of each metal.
Each metal species may comprise electrically sediments / composition of about 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30% , 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, 99.9 %, 99.99%, 99.999%, or 100%.
[0043] Layer (periodic layer) as described herein wherein the nano-laminate comprising brass zinc content by weight of between 1% and 90% and the copper content change between 10% and 90% of the change.
In one embodiment, at least one of the periodic layer comprises zinc at a concentration between 1% and 90% with a brass alloy.
In another embodiment, at least half the periodic brass alloy layer comprising zinc at a concentration between 1% and 90% of the change.
In another embodiment, all of the periodic layer comprises zinc at a concentration between 1% and 90% with a brass alloy.
In one embodiment, the zinc content by weight of from about 50% to about 68%, about 72% to about 80%, about 60% to about 80%, about 65% to about 75%, about 66% to about 74 %, about 68% to about 72%, about 60%, about 65%, about 70%, about 75% or about 80%.
In other metal or metalloid (such as silicon) is present in the nano-laminate brass articles / components or coating layer or layers (periodic layer), the other metals are generally may comprise, by weight of the layer composition 0.01% to 15%.
In one embodiment, the total amount of other metals and / or metalloid is less than 15% by weight, 12%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.2%, 0.1%, 0.05% or 0.02%, but greater than about 0.01% in each case.
[0044] In one embodiment, the coating may have a coating according to the nature of the subject to the protection of the coating material or the environment and changing the coating thickness.
In one embodiment, the total thickness of the nano-laminate brass coating (e.g., a desired thickness) at 10 nanometers and 100,000 nanometers (100 microns), between 10 nm and 400 nm, 50 nm and 500 nm, between 1000 nanometers and 100 nanometers, 1 micrometer to 10 micrometers, 5 micrometers to 50 micrometers, 20 micrometers to 200 micrometers, 40 micrometers to 100 micrometers, 50 micrometers to 100 micrometers, 50 micrometers to 150 micrometers, 60 micrometers to 160 micrometers, 70 micrometers to 170 micrometers, 80 micrometers to 180 micrometers, 200 micrometers to 2 millimeters (mm), 400 micrometers to 4mm, 200 m to 5mm, 1mm to 6.5mm, 5mm to 12.5mm, 10mm to 20mm, and 15mm to 30mm.
[0045] In one embodiment, the coating has a thickness sufficient to provide a surface modification.
In one embodiment, the total thickness of the nano-laminated plastic substrate brass coating is between 50 and 90 microns.
In another embodiment, the total thickness of the nano-laminated plastic substrate brass coating between 40 and 100 microns, or between 40 and 200 microns.
Can be modified, such as by mechanical polishing, electro-polishing and polishing method of adjusting the surface acid exposure category.
Polishing can be mechanical and removed from the coating thickness is less than about 20 microns.
In one embodiment, the plastic or polymeric substrate brass coating has a thickness less than 100 microns, for example, the entire coating is between 45 and 80 microns changes, for example, gave an average thickness of 70-80 microns .
In one embodiment, the nano-laminate polishing or electro-polishing brass coating as an arithmetic mean roughness (Ra) of less than about 25,12,10,8,6,4,2,1,0.5, 0.2, 0.1, 0.05,0.025 or 0.01 m surface.
In another embodiment, the average surface roughness of less than about 4,2,1,0.5,0.2,0.1,0.05,0.025 or 0.01 microns.
In another embodiment, the average surface roughness of less than about 0.05 microns or 2,1,0.5,0.2,0.1
[0046] Nano laminated brass coating, the article or article assembly may include any number of suitable thickness having a desired layer (e.g., layer 2 to 100,000).
In some embodiments, the coating may contain 2, 3, 4,5,6,7,8,9,10,12,14,16,18,20,22,24,26,28,30,35, 40,45,50,60,70,80,90,100,150,200,250,300,350,400,450, 500,600,700,800,900,1,000,1,500,2,000,2,500,3,000, 4,000, 5,000,7,500,1,000,2,000,4,000,6,000,8,000,10,000,20,000,40,000, 60,000,80,000 or 100,000 layers, or more layers of electrodeposited material, wherein each layer may be about 2nm-2,000nm (2 microns).
In some embodiments, the thickness of each layer is about 2nm-10nm, 5nm-15nm, 10nm-20nm, 15nm-30nm, 20nm-40nm, 30nm-50nm, 40 nm-60nm, 50nm-70nm, 50nm-75nm, 75nm -100nm, 5nm-30nm, 15nm-50 nm, 25nm-75nm, or 5nm-100nm.
In other embodiments, the thickness of each layer is about 2nm to 1,000nm, or 5nm to 200nm, or 10nm to 200nm, or 20nm to 200nm, 30nm to 200nm, or 40nm to 200nm, or 50nm to 200nm.
[0047] Nano laminated brass coating, the article or article component may comprise layers series organized in various ways.
In some embodiments, the micro structure in the electrodeposition species (metal and / or metalloid composition) and / or electrical types of mutually different sediment layers in a repeating pattern is deposited.
Although a Class layer may occur more than once in a repeated coating or article, but its thickness may be the same or different in each case, such layer appears.
Nano laminated brass coatings, articles or components of articles may comprise two, three, four, five or more layers, which may or may not be repeated in a specific pattern.
[0048] As a non-limiting example, the microstructure can be electrically sediments species (metal and / or metalloid composition) and / or the electrical aspects of different types of sediment layers a, b, c, d and e marked and di e.g. element (a, b, a, b, a, b, a, b, ...), three yuan (a, b, c, a, b, c, a, b, c, a, b, c, ...), quaternary (a, b, c, d, a, b, c, d, a, b, c, d, a, b, c, d ...), five yuan (a, b , c, d, e, a, b, c, d, e, a, b, c, d, e, a, b, c, d, e ...) And other organizations alternating pattern.
Can also be other arrangements such as (c, a, b, a, b, c, a, b, a, b, c ...), (c, a, b, a, b, e, c, a , b, a, b, e ...) And the like.
[0049] In some embodiments, by electrodeposition methods described herein have a different composition comprising nano-laminated brass 2,3,4, 5 or 6 with different sediment types of electrical and / or electro deposit different amounts of or more layers.
In some embodiments, by electrodeposition methods described herein have nano laminated brass containing 2,3,4,5,6 or more layers having different microstructures.
[0050] In other embodiments, the nano-laminate comprising a combination of brass with different compositions and different layers of different microstructures.
Thus, for example, in some embodiments, as described herein was prepared nano brass coating and lamination assembly having a first layer, and comprises (i) in an amount different from the first electrically sediments species / species aspect layer is at least one layer, and (ii) unlike in the microstructure of the first layer is at least one layer, wherein the electrical and microstructural aspects sediment species different layers may be the same or different layers.
[0051] In some embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and at least two mutually different types of sediments in the amount of the electric and / or species aspect, and (ii) different from the first layer is at least one layer in the microstructure.
In some embodiments, the nano-laminate having a first layer of brass, and comprises (i) is different from the amount of the electric sediment types and / or kinds of aspects of the first layer at least one layer, and (ii) in the microstructure differs from the first layer and at least two layers different from each other.
In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and at least two layers different from each other, and (ii) the amount of electrodeposit species and / or species aspects different from the first layer and at least two layers different from each other in terms of the microstructure.
In each case, in terms of the electrodeposit species and / or microscopic structure of different layers may be the same or different layers.
[0052] In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and the at least three layers different from each other in the amount of electrodeposit species and / or the type of connection, and (ii) different from the first layer and at least two layers different from each other in terms of the microstructure.
In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and at least two layers different from each other, and (ii) the amount of electrodeposit species and / or species aspects different from the first layer and different from each other in terms of at least three layers microstructure.
In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and the at least three layers different from each other in the amount of electrodeposit species and / or the type of connection, and (ii) different from the first layer and different from each other in terms of at least three layers microstructure.
In each case, in terms of the electrodeposit species and / or microscopic structure of different layers may be the same or different layers.
[0053] In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and the at least four layers different from each other in the amount of electrodeposit species and / or the type of connection, and (ii) different from the first layer and the at least four layers different from each other in terms of the microstructure.
In other embodiments, the nano-laminate having a first layer of brass, and comprises (i) different from the first layer and at least five different from each other in the amount of electrodeposit species and / or the type of connection, and (ii) different from the first layer and at least five different from each other in terms of the microstructure.
In each case, in terms of the electrodeposit species and / or microscopic structure of different layers may be the same or different layers.
[0054] EXAMPLE
[0055] Example 1.
Nano-laminated brass deposition
[0056] The following examples describe the method for preparing may be deposited on a plastic or polymeric substrate electrodeposition coating or nano-laminate brass cladding.
[0057] Prior to any metal deposited on the surface of the electrolytic plastic or polymeric substrate, using a commercial electroless nickel plating (or electroless copper plating) was performed on a substrate to form an electroless plating thickness is typically 2-3 microns conductive coating .
There was then immersed substrate e- nickel coating 50% saturated aqueous HCl (about 10.1% HCl) in 2 minutes or until bubble formation was observed.
Then washed with water base.
[0058] The substrate is immersed in commercial cyanide copper - zinc plating bath (from Electrochemical Products Inc.
(EPI) of the E-Brite B-150Bath), which comprises CuCN (29.95g / l), ZnCN (12.733g / l), free cyanide (14.98g / l), NaOH (1.498g / l), Na2CO3 ( 59.92g / l) E-Brite TM B-150 by volume 1%, Electrosolv TM by volume of 5%, E-Wet TM 0.1% by volume.
The pH of the bath changes from 10.2 to 10.4, plating temperature is 90-120 ?.
The anode than the cathode of the ratio of 2 to 2.6 to 1, wherein the anode has an alloy 260 or rolling or calendering 70/30 (Cu / Zn) brass.
By 15ft / min moving cathode, or per foot jet pipes 2 cubic feet of air / min at a flow rate of air injection to provide agitation.
[0059] By applying a continuous 1.9 seconds of 42.2mA / cm 2 pulse then 0.25 s 0mA / cm 2 pulse (telogen) waveform composed of a total duration beginning electrodeposition 10 minutes.
Immediately prior to application of the waveform after the 10 minutes, applying a second waveform 6 hours 40 minutes, the second waveform by nine seconds of 20 mA / cm 2 pulses, then one second of 155mA / cm 2 pulse, and then 0.4 seconds The -155mA / cm 2 stripping (stripping) (reverse) pulses.
In the electrodeposition process, the need for preventing passivation of the anode, the anode to be cleaned.
If necessary, at 2 hour intervals for the anode cleaning, then you need to stop the electrodeposition process.
[0060] The method nano laminated brass coating applied to the substrate, the coating having a thickness of 40 to 50 nm (about 44nm) of the periodic layer.
The total thickness of the coating was about 100 microns.
[0061] Example 2 had tensile properties of the samples with and without nano ABS laminated brass reinforced
[0062] ASTM D638 test utilizing nano-coated polymer laminate brass dog bone-shaped samples.
By from acrylonitrile butadiene styrene (ABS) sheet to laser cutting dogbone geometry specified in ASTM standard tensile specimens were prepared.
Then using the method described in Example 1. These coated substrates.
Use Instron Model4202 tensile test stand test.
[0063] Maximum tensile strength results obtained are plotted in Figure 1, this figure provides a contrast ratio of the maximum tensile strength increased with coating thickness, indicates that the maximum tensile strength of the coating directly proportional to the thickness.
Specifically, the maximum tensile strength, a brass coating nano-laminated portion to R 2 = 0.9632 The strong correlation exhibits a linear increase with the thickness.
Tests show that compared with the uncoated substrate, nano-laminated coating thickness of 95 microns maximum tensile strength by up to 500%.
[0064] Tensile tests are also given modulus of elasticity (stiffness) data.
Figure 4 shows a coating thickness (in cross-sectional representation of metal%) of the stiffness function improvement.
As shown, when the nano-laminated brass (respectively) representing the test sample cross-sectional area of ??~ 10 to 20%, the nano-laminate coating increased the elastic modulus of about 3 to 7 times.
[0065] Figure 3B shows the modulus of elasticity "Stiffness Ratio" expressed improvement, i.e., the laminate coating has a stiffness nano sample of uncoated samples of the specific rigidity, also shows the ratio of the cross section with the nano-laminate layer 10 from % to 20%, an increase of 3-7 times the stiffness.
[0066] 3, image A, described with respect to the uncoated sample of ABS, nano-laminates of different thicknesses brass ABS effect on the sample.
ABS 100 samples have been laminated Micro and Nano brass coating, for being laminated brass coating nano 1% cross-sectional area occupied by each, showing at least 10% of the flexural modulus increase.
For being occupied nano coating lamination brass cross-sectional area per 1%, with an average growth elasticity modulus is greater than about 20%.
[0067] Example 3 samples had flexural properties of ABS with and without nano-reinforced laminated brass
[0068] Different from the thickness (1/8 and 1/16 inch) samples were cut ABS sheet substrate, and nano-laminate according to embodiment 1, wherein said brass coating thickness of 100 microns Example coating.
Flexural modulus measured in accordance with ASTM D5023.
The results are shown in Figure 2, picture A, is provided below with respect to control ABS sheet data.
1/8 ABS elastic modulus improved 300%, while the flexural modulus increased by 400%.
Similarly, for 1/16 ABS, the flexural modulus is not improved by 400%, but increased beyond 600%.
[0069] Preparation Example 4 and the bending test uniform nano laminated, and the structural framework of the uncoated
[0070] To quantify the difference between the brass coating and the nano-laminate uniformly between the brass alloy coating, the use of direct current (DC) at an average current density of the specified control sample (a plastic frame member in this case) plating.
At the end of the plating is sufficient to produce 80 m thick in the embodiment according to parts prepared nano-laminated brass coating, DC control is only plated plastic frame 30 micron non-laminated brass.
Control thickness smaller because DC brass plated to significantly slower plating speed, the plating speed is slow, and as a plating time becomes limited by the thickness.
Thus, by contrast, a uniform DC plating brass member can not achieve the desired thickness.
Thus, the use of pulse plating technology to produce a uniform (non-laminated) member brass coating to achieve the desired thickness 80 microns, and in order to compare with the member 80 having a laminated Micro and Nano brass coating provides a uniform coating components.
[0071] Utilization adjusted to accommodate the particular component geometry ASTM D5023, of uniform coating thickness of the coating member 80 microns, having a thickness of 80 microns nano laminated brass coating member and uncoated plastic parts were evaluated and contrast.
Load results show that for a constant deflection of 0.10 inches, a brass coating nano-laminated member, with respect to the uncoated parts, having a maximum tensile strength of about 270% increase, relative to the brass coating layer having a uniform components, the maximum tensile strength increased by 20%.
The test results are shown in the following table:
[0073] Load results show that, compared with a uniform coating, layer changes, the nano-laminate coating makes it significantly increased strength.
[ Machine Translation ]
Electrodeposited, nanolaminate
coatings and claddings for corrosion protection
CN102639758
CN102639758
Described herein are electrodeposited corrosion-resistant multilayer coating and claddings that comprises multiple nanoscale layers that periodically vary in electrodeposited species or electrodeposited microstructures. The coatings may comprise electrodeposited metals, ceramics, polymers or combinations thereof. Also described herein are methods for preparation of the coatings and claddings.
DESCRIPTION
[0001] This application claims the June 8, 2009 to submit topics for plating nano-laminates for corrosion protection Coating and U.S. Provisional Application priority cladding 61 / 185,020, which is hereby by reference in Incorporated herein.
[0002] BACKGROUND
[0003] Laminated metal, especially nano-laminated metal, because of its unique toughness and fatigue resistance and Thermal stability, their structure and thermal applications for people interested.
However, for anti-corrosion Reported words, at the nanometer level is formed by laminating an anti-corrosion coating of success is relatively small.
[0004] Plating has been successfully used to laminate the nano-coating is deposited on the metal and alloy components, For various engineering applications. Plating was known to form a dense coating of any conductive substrate of Low-cost method. Has proven a viable means of producing nano-plating for laminated coating, where individual
The laminate may be composed of metal, ceramic or organometallic composition or other microstructural features of the Change.
By varying the plating parameters (such as current density, bath composition, pH, stirring rate, and / Or temperature) can generate multi-laminated material in a single bath.
Alternatively, the mandrel or group Transfer from one bath to another bath, each of said bath to maintain a constant expressed different combinations of parameters,
Can achieve multi-laminated material or coating.
[0005] Organic, ceramic, metal and metal-containing coating corrosion resistance of them depends on the Properties, microstructure, adhesion, thickness, and they are covered by the electrochemical interaction of the matrix With.
In the case of the sacrificial metal or metal-containing coatings, such as zinc in the case of iron-based substrate, and the coating
Layer of the substrate is less than the negative, and therefore the occurrence of preferential oxidation of the coating, thereby protecting the substrate.
Because these coatings provide a sacrificial layer by preferential oxidation protection, even if they are scratched or rubbed
Injury will also continue action.
Sacrificial coating performance greatly depends on the rate of oxidation of the coating and the sacrifice
The thickness of the sacrifice layer.
The matrix only at the expense of anti-corrosion coating is subsisting at the proper position, and may
According to the environment and the coating is subjected to a coating resulting from the oxidation rate varies.
[0006] Alternatively, in the case of a barrier coating, such as nickel in the case of iron-based substrate, the coating ratio of the
More electronegative matrix, and therefore the corrosion by forming a barrier layer of oxide is generated effect.
In A
Type metals, such as Fe, Ni, Cr and Zn, is substantially higher electronegativity, inert (non-reactive) higher.
When the coating is more inert than the matrix, if the coating is scratched in any way or abrasions, or
If you are not completely cover, these coatings will not have an effect, and may accelerate in the matrix: Coating
Development of corrosion at the interface of the substrate, resulting in preferential corrosion of the substrate.
When using the ceramic coating also
Is true.
For example, the prior art has been reported, although the TiN coating fully dense than steel and aluminum
Against the corrosive environment on a variety of more inert, holes may occur during the processing of these coatings and micro-
Holes on their corrosion resistance negatively.
In the case of the barrier coating, the coating apertures can
By depression, cracks or galvanic corrosion mechanism to accelerate the corrosion of the underlying metal.
[0007] Many methods have been applied to the barrier layer to improve the corrosion resistance of the coating, such as by the use of a metal
The intermediate layer or layers programs to reduce pinhole defects.
This basic method for reducing the possibility of defects or
Reduce failures sensitivity defects, scratches or abrasions case.
An example of a multi-layer solution is generally
In industrial coatings deployment visible operation, comprising the use of the primer, the primer coating comprises sacrifice
Sacrifice metal (e.g. zinc), highly cross-linked with a low surface energy topcoat (e.g. fluorinated or polyurethane
Topcoat) combined.
In this case, the outer coating layer as an etch stop layer.
In case the outer coating
Integrity damaged for any reason, the metal contained in the primer can be used as the sacrificial medium, by
This sacrificial protection of the substrate from corrosion.
[0008] Zinc is used to represent a component of any alloy is etched away, while the other part more or less
The term is left in place.
This phenomenon may contain a high percentage of zinc in brass is the most common,
However, aluminum bronze and other chemical affinity wide variety of metal alloys, the same or parallel
Phenomenon is common.
Zinc is usually to clear the border area becomes evident, and the original and the alloy phase
Ratio, which has more of an inert metal becomes concentrated.
In the case of brass, zinc is usually almost completely
Removed, and copper is almost pure form, but a very weak mechanical state.
To cause corrosion of zinc is usually
Depends on the electrochemical differences between the different kinds of metals, as well as environmental conditions cause corrosion.
Alloy
Zinc leads to the loss of overall structural integrity of the alloy, and is considered to be a most aggressive
Types of corrosion.
[0009] Can present the best barrier coating and the sacrificial coating is more inert than the coating of the substrate, and
And a coating layer formed on the etching barrier layer, but in case the lossy coating, which is more than the inert matrix
Low, and resistance to corrosion sacrifice, thereby protecting the substrate from direct corrosion.
[0010] SUMMARY
[0011] Summary of the Invention
[0012] In one embodiment of the techniques described herein, when the zinc alloy to a phenomenon observed
Be used to make both better off than the inert matrix than the less inert matrix as a corrosion-resistant coating layer, and
And which by both as a barrier layer also acts as a sacrificial coating to protect the role of the matrix.
This technique other Embodiments and advantages will become apparent upon consideration of the content below.
[0013] In one embodiment, the techniques described herein comprises a multilayer plating of corrosion resistant coating or
Cladding, which comprises a plurality of layers of nanoscale microstructure their species or substances in the plating plating
(The kind of substance microstructure plating) on ??the periodic variations, wherein said plating substance or plating species
Said layer of a change in the type of material microstructure results in an electrochemical interaction between these layers
With, in the nanoscale layer interface therebetween.
[0014] The techniques described herein also provide for the production of corrosion-resistant plating side multi-layer coating or cladding
Method, comprising the steps of:
[0015] a) coating the core will be placed in the mold or matrix containing one or more metal ions, ceramic particles,
Polymer particles, or a combination of the first electrolyte; and
[0016] b) applying a current and timely change one or more of: amplitude of the current, electrolyte temperature,
Electrolyte concentration of the additive, or electrolytes agitated to produce periodic layer plating species, or electrical
Plating layer species periodic microstructure; and
[0017] c) Under such conditions growth multilayer coating, until the desired thickness of the multilayer coating.
[0018] This method may further comprise the step (d) after step (c), which comprises removing from the bath
The mandrel or the matrix and washed.
[0019] The techniques described herein further provides for the production of electrical multilayer corrosion-resistant coating or cladding
Plating method, comprising the steps of:
[0020] a) coating the core will be placed in the mold or matrix containing one or more metal ions, ceramic particles,
Polymer particles, or a combination of the first electrolyte; and
[0021] b) applying a current and timely change one or more of: amplitude of the current, electrolyte temperature,
Electrolyte concentration of the additive, or electrolytes agitated to produce periodic layer plating species, or electrical
Plating layer species periodic microstructure; and
[0022] c) under such conditions nm thickness layer is grown; and
[0023] d) will be the coated substrate is placed on the mandrel or containing one or more metal ions is different from
Said first electrolyte second electrolyte, the electrolyte comprises a second metal ion, the ceramic particles
Tablets, polymer particles, or combinations thereof; and
[0024] e) repeating steps (a) to (d), until the desired thickness of the multilayer coating.
[0025] Wherein step (a) to (d) are repeated at least twice.
This method may further comprise after step (e)
Step (f), which comprises removing the mandrel or the covered substrate from the bath and washed.
[0026] Also described herein is an anti-corrosion coating or cladding multilayer electroplating, which comprises a plurality of nanoscale
Layers, which periodically changes in microstructure plating species, leading to these changes in these layers
Electrochemical interactions between layers.
Also described is a multilayer coating or corrosion-resistant cladding, which package
Comprising a plurality of nanoscale layer, which changes in plating species, leading to changes in these layers between the layers
Electrochemical interactions.
[0027] Coating and cladding described herein due to oxidation, reduction, stress, dissolve, to zinc, acid,
Bases, such as resistance to corrosion or sulfidation.
[0028] Brief Description
[0029] Figure 1 shows a preferred embodiment having the "multilayer coating" matrix diagram (Fig. 1
Left), and a schematic view of the prior art known to have "uniform coating" of the substrate (Fig. 1 right).
The left side And the right side schematic view of an exemplary demonstration of both the coating pinholes, pores or damage with respect to each Matrix shown at the bottom of the sequence with time (Fig. 1 to the top to the bottom of the order).
This schematic Shows some typical layer, which is not to scale and the substrate.
In a typical embodiment, Coating the nanometer range, and there is further shown a number ratio of FIG.
[0030] Details
[0031] In one embodiment, there is provided a plating corrosion by a thickness of a single layer composed of nanoscale Eclipse multilayer coating.
In such an embodiment, the monolayer may be negative and the adjacent layers of different electrically.
[0032] In other embodiments, the present technology provides a multi-layer anti-corrosion coating or cladding (referred to here as "Coating"), which comprises a metal, alloy, polymer, or nanoscale ceramic component, or a combination thereof On the composition of a plurality of layers there is a change (referred to here as "plating species").
[0033] In such an embodiment, the composition changes between the lead layer of these layers with electrochemical Interaction.
[0034] In another embodiment, the present technology provides a multi-layer anti-corrosion coating, which comprises a plurality of nano Meter-layer, their size, crystal orientation, the grain boundary geometries, or combinations thereof (collectively referred to herein as "(multi-A) plating species microstructure ") having a layer change, resulting in changes in the layer between the layers of electrically
Learning interactions.
[0035] In another embodiment, there is provided a multi-layer coating or cladding layer is a case, wherein the layers The electronegativity or inert changes, and wherein the corrosion rate can be controlled by the adjacent layer electrically negative Or reactive (or "inert") to be controlled.
[0036] An embodiment of the present technology provides a multi-layer coating or cladding layer, wherein the periodic layers Less inertia than the other one, and less than the inert substrate, thereby forming the multilayer coating To periodically sacrificial layer.
[0037] "Periodically varying layer" used herein indicates a series of two or more non-like
With a layer (non-equivalent "periodic layers"), which is repeatedly applied to the underlying surface or mandrel.
Non-identical
Series of layers may comprise two or more layers of non-identical simple interactive sample (e.g., layer 1, layer 2, layer 1, layer 2, etc.), or in another embodiment, may comprise three or three
One or more non-identical layer (e.g., layer 1, layer 2, layer 3, layer 1, layer 2, layer 3, etc.).
More Samples can involve complex interactive two, three, four, five or more layers are arranged at a constant or variable sequence
Layer (e.g., layer 1, layer 2, layer 3, layer 2, layer 1, layer 2, layer 3, layer 2, layer 1, and so on).
In one embodiment, a series of two layers are alternately applied 100 times, to provide a total of 200 layers,
Layers 100 and 100 having a first type of periodic layer layer layer periodicity of the interaction of a second type,
Wherein the first and second periodic layers of different types.
In other embodiments, the "cyclic change
Of layer "includes 2 or more, 3 or more, 4 or more, 5 or more layers, which is repeatedly applied about
5,10,20,50,100,200,250,500,750,1,000,1,250,1,500,1,750,
2,000,3,000,4,000,5,000,7,500,10,000,15,000,20,000 or more times.
[0038] When used herein, "periodic layer" single "layer of periodically varying" among.
[0039] In another embodiment, the present technology provides a multi-layer coating or cladding layer, wherein the periodic layer One more inert than the other, and it is more inert than the substrate, thereby forming the multilayer coating To periodically corrosion barrier.
[0040] In another embodiment, the present technology provides a multi-layer coating, wherein one of the periodic layer than Adjacent layers are less inert, and all layers of the substrate is less than inert.
[0041] In yet another embodiment, the present technology provides a multi-layer coating or cladding layer, wherein the periodic layer One more inert than the adjacent layer, and all layers of the substrate is more than inert.
[0042] An embodiment of the present technology provides a multi-layer coating or corrosion-resistant cladding composition comprising Single layer, wherein the layers are not separated, and the presentation and the adjacent diffusion layer interface. In some embodiments, The diffusion region between these layers may be 0.5,0.7,1,2,5,10,15,20, 25,30,40,50,75,100,200,400,500,1,000,2,000,4,000,6,000, 8,000 or 10,000 nanometers.
In other embodiments, the diffusion region between layers may be 1-5, Or 5-25, or 25-100, or 100-500, or 500 to 1,000, or 1,000 to 2,000,
Or 2,000 to 5,000, or 4,000 to 10,000 nanometers.
Various methods can be used to control the diffusion boundary The thickness of the surface, including the variation rate of the plating conditions.
[0043] Another embodiment of the technology described herein provides for producing a multilayer anti-corrosive coating
Method, the coating comprises a plurality of layers of nanoscale ("nano-laminate"), which in an electroplating or plated metal species
Or a combination thereof on the seed microstructure changes, these layers are generated by the electroplating process.
[0044] When electroplating species or combinations thereof changes, in some embodiments, the plated metal
Species may include one or more of Ni, Zn, Fe, Cu, Au, Ag, Pd, Sn, Mn, Co, Pb,
Al, Ti, Mg and Cr, Al2O3, SiO2, TiN, BoN, Fe2O3, MgO, and TiO2, ring
Epoxy resin, polyurethane, polyaniline, polyethylene, polyetheretherketone, polypropylene.
[0045] In other embodiments, the plating species may include one or more metals selected from
Ni, Zn, Fe, Cu, Au, Ag, Pd, Sn, Mn, Co, Pb, Al, Ti, Mg and Cr.
Alternatively, these metals may be selected from: Ni, Z n, Fe, Cu, Sn, Mn, Co, Pb, Al, Ti,
Mg and Cr; or is selected from Ni, Zn, Fe, Cu, Sn, Mn, Co, Ti, Mg and Cr; or selected from
Since Ni, Zn, Fe, Sn, and Cr.
The metal may exist in any percentage.
In such an embodiment
, The percentage of each metal can be selected individually for the plating species about 0.001,0.005,
0.01,0.05,0.1,0.5,1,5,10,15,20,25,30,30,35,40,45,50,
55,60,65,70,75,80,85,90,95,98,99,99.9,99.99,99.999 or
100%.
[0046] In other embodiments, the plating species may include one or more ceramic (e.g., gold
A metal oxide or metal nitride), which is selected from Al2O3, SiO2, TiN, BoN, Fe2O3, MgO,
SiC, ZrC, CrC, diamond particles, and TiO2.
In such an embodiment, each of the ceramic
The percentage may be selected individually for about 0.001,0.005,0.01,0.05 plating species,
0.1,0.5,1,5,10,15,20,25,30,30,35,40,45,50,55,60,65,
70,75,80,85,90,95,98,99,99.9,99.99,99.999 or 100%.
[0047] In still another embodiment, the plating species may include one or more polymers selected from the group
Since the epoxy resin, polyurethane, polyaniline, polyethylene, polyetheretherketone, polypropylene, and poly (3,4-ethylenedioxythiophene
Alkylene dioxythiophene) poly (styrene sulfonic acid).
In such an embodiment, the percentage of each polymer
May individually be selected for the plating species about 0.001,0.005,0.01,0.05,0.1,0.5,
1,5,10,15,20,25,30,30,35,40,45,50,55,60,65,70,75,
80,85,90,95,98,99,99.9,99.99,99.999 or 100%.
[0048] Electroplating another embodiment of the present technology provides for the production of nano-laminate, the corrosion-resistant coating
The method, which reduces the through-hole defects in the overall corrosion-resistant coating.
This method comprises a multi-layer coating or package
Layer is applied to the substrate or mandrel method of Figure 1 shown on.
[0049] As shown in Figure 1 left, the preferred embodiment of the multi-layer coating is arranged to cover the substrate having
Two interactive (light and dark) layer.
In the embodiment of Figure 1 left, the bright layer is a protective layer, the dark layer
As a sacrificial layer.
As shown in sequence, over time, the bright layer is slightly parallel to the east
Direction of the substrate surface to start, and in the dark of the damaged layer of sacrificial layer beneath the light parallel to the
Direction of the surface of the substrate is consumed.
Also note that the multi-layer coating of the outermost (exposed) layer holes are not
Expanded to break the bore disposed between the substrate and a second bright layer, thereby protecting the substrate from corrosion
Eclipse.
In a preferred embodiment, the etching is limited to the relatively non-inert layer (dark layer), these are the female
Polarity protection, and the corrosion level rather than toward the substrate is subjected to.
[0050] Uniform coating of the right as shown in Figure 1, the prior art is arranged to cover the substrate having a single
Layers.
If the sequence is shown, over time, to the monolayer hole perpendicular to the substrate surface
Direction of expansion, until finally reach the substrate, which then corrosion or other forms of degradation.
[0051] In one embodiment, the techniques described herein describes a single bath by
Electroplating process producing a multilayer, laminated coating nano method comprising the steps of:
[0052] a) coating the core will be placed in the mold or matrix containing one or more metal ions, ceramic particles,
Polymer particles, or a combination of the first electrolyte; and
[0053] b) applying a current and timely change one or more of: amplitude of the current, electrolyte temperature,
Electrolyte concentration of the additive, or electrolytes agitated to produce periodic layer plating species, or electrical
Plating layer species periodic microstructure; and
[0054] c) Under such conditions growth multilayer coating, until the desired thickness of the multilayer coating.
[0055] This method may further comprise the step (d) after step (c), which is removed from the bath of the core
The die or matrix and washed.
[0056] The techniques described herein are also elaborated in two or more sequential plating bath multilayer
Nano laminate coating or cladding, comprising the steps of:
[0057] a) coating the core will be placed in the mold or matrix containing one or more metal ions, ceramic particles,
Polymer particles, or a combination of the first electrolyte; and
[0058] b) applying a current and timely change one or more of: current, electrolyte temperature, electrolyte
Additive concentration, or electrolytes agitated to produce periodic layer plating species, or plating species
Periodic microscopic structure; and
[0059] c) under such conditions nm thickness layer is grown; and
[0060] d) will be the coated substrate is placed on the mandrel or containing one or more metal ions is different from
Said first electrolyte second electrolyte, the electrolyte comprises a second metal ion, the ceramic particles
Tablets, polymer particles, or combinations thereof; and
[0061] e) repeating steps (a) to (d), until the desired thickness of the multilayer coating; wherein repeating steps (a)
To (d) at least twice.
[0062] This method may further comprise the step (f) after step (e), which is removed from the bath of the core
Or covering matrix mold and washed.
[0063] Corrosion-resistant multi-layer coating can be generated on the mandrel, rather than directly on the substrate to generate, in order to
Producing free-standing material or cladding.
Cladding layer thus formed can be attached in any other way to the
Matrix, including welding, gluing or other bonding material.
[0064] The multi-layer coating may comprise an aqueous solution containing from electrodeposited metal layer, such as Ni, Zn,
Fe, Cu, Au, Ag, Pd, Sn, Mn, Co, Pb and Cr.
The multi-layer coating may also include
Alloys of these metals, including but not limited to: ZnFe, ZnCu, ZnCo, NiZn, NiMn, NiFe,
NiCo, NiFeCo, CoFe, CoMn.
The layers may also include a molten salt or ionic liquid solution from
Electrolytic deposition of a metal.
Which comprises previously listed metal, and other, including but not limited to, Al,
Mg, Ti and Na.
In other embodiments, the multilayer coating may comprise one or more metals,
Selected from Ni, Zn, Fe, Cu, Au, Ag, Pd, Sn, Mn, Co, Pb, Al, Ti, Mg
And Cr.
Alternatively, one or more metals to be electrodeposited can be selected from: Ni, Zn, Fe, Cu,
Sn, Mn, Co, Pb, Al, Ti, Mg and Cr; or is selected from Ni, Zn, Fe, Cu, Sn, Mn,
Co, Ti, Mg and Cr; or is selected from Ni, Zn, Fe, Sn, and Cr.
[0065] The multi-layer coating may comprise an aqueous liquid solution or ion electrode electrodeposited ceramic
And polymers, including but not limited to, Al2O3, SiO2, TiN, BoN, Fe2O3, MgO, and
TiO2.
Suitable polymers include, but are not limited to, epoxy resin, polyurethane, polyaniline, polyethylene
Alkenyl, polyether ether ketone, polypropylene.
[0066] The multi-layer coating may also include a combination of metal and ceramic, metal and polymer, as described above
Metals, ceramics and polymers.
[0067] The monolayer (layer nanoscale) the thickness may vary greatly, for example, at 0.5 and 10,000
Varies between nanometers, and in some embodiments, each layer is about 200 nm.
The single (nanoscale
The thickness of the layer) may also be from about 0.5,0.7,1,2,5,10,15,20,25,30,40,50,
75,100,200,400,500,1,000,2,000,4,000,6,000,8,000 or 10,000
Nm.
In other embodiments, these layers may be about 0.5 to 1, or 1-5, or 5-25,
Or 25-100, or 100-300, or 100-400, or 500 to 1,000, or 1,000 to
2,000, or 2,000 to 5,000, or 4,000 to 10,000 nanometers.
[0068] A single layer may have the same or different thicknesses.
Periodically varying layer thickness can also be varied.
[0069] The total thickness of the coating or cladding layer may vary greatly, e.g., in 2 m and 6.5 mm
Changes between or above.
In some embodiments, the total thickness of the coating or cladding can also 2
Nm to 10,000 nm, 4 nm to 400 nm, 50 nm to 500 nm, 100 nm
1,000 nanometer, 1 micrometer to 10 micrometers, 5 micrometers to 50 micrometers, 20 micrometers to 200 micrometers, 200
Micrometers to 2 millimeters (mm), 400 micrometers to 4mm, 200 m to 5mm, 1mm to 6.5mm,
5mm to 12.5mm, 10mm to 20mm, 15mm to 30mm.
[0070] In addition to other factors, can be controlled by applying a current in the layer thickness of the electroplating process.
This technique involves applying a current to the substrate or mandrel, so that the coating or cladding layer is formed on the substrate or
Core die.
The current may be applied continuously, or more preferably, according to a predetermined pattern (e.g., waveform)
Is applied.
In particular, the waveform (eg, sine, square, ramp, or triangular wave) can
Is intermittently applied to facilitate the electroplating process, intermittently reversing the electroplating process, to increase or
Reduced deposition rate, change the composition of the deposited material, or to provide a combination of such techniques, in order to achieve
Particular layer thickness or a particular pattern of the different layers.
Current density and cycle of the waveform can be changed individually
Technology.
In some embodiments, the current density may be continuous or discrete variation, which range from 0.5
And between 2000mA / cm2.
Other current density ranges are possible, for example, the current density can yl
Surface area to the substrate or mandrel to be covered between the following range: approx. 1 and
Between 20mA / cm2; between about 5 and 50mA / cm2S; between about 30 and 70mA / cm2; 0.5 and
Between 500mA / cm2; 100 and 2000mA / cm2; greater than about 500mA / cm2; about 15 and
40mA / cm2 between.
In some embodiments, the frequency of the waveform can I about 0.01Hz to about
50Hz.
In other embodiments, the frequency may be: from about 0.5 to about 10Hz; 0.02 to about 1Hz
Or from about 2 to 20Hz; or from about 1 to about 5Hz.
[0071] The multi-layer coating and a cladding described herein is suitable for all kinds of coating or cladding corrosion sensitive group
Quality.
In one embodiment, the substrate may be particularly suitable for coating by the corrosive material (such as iron,
Steel, aluminum, nickel, cobalt, iron, manganese, copper, titanium, alloys, reinforced composite materials or the like)
The matrix is ??made.
[0072] Coating and cladding described herein may be used to prevent many types of corrosion, including, but not
Limited to, by oxidation, reduction, stress (stress corrosion), was dissolved, to zinc, acid, alkali, vulcanization, etc.
Such as corrosion caused.
[0073] DETAILED DESCRIPTION
[0074] Example 1
[0075] Include zinc - Preparation of nanoscale iron alloy layer of a multilayer coating, wherein the concentration of iron in the adjacent
Layer change.
[0076] Business plating solution formula with MacDermid Inc. (Waterbury, CT, USA) supply
Generate zinc - iron bath.
The bath composition is described in Table 1.
[0077] Table 1.
Plating solution in Example
[0080] The steel panel was immersed in the bath and connected to a power source.
Providing the power generated in the computer
25mA / cm2 (continued 17.14 seconds) and 15mA / cm2 alternately (duration 9.52 seconds) between the rectangular waveform
Waveform source combinations.
The total plating time M90 ??coat (0.9 ounces per square foot coating) is about 1.2 small
Time.
The layer is deposited about 325, in order to achieve the total thickness of 19µm.
Layer thickness between 50 and 100 nm
Between meters.
[0081] In accordance ASTMB117 (salt spray operation standards) corrosive environment to test the coating, in
Showed no signs of red rust after 300 hours of exposure.
[0082] Example 2
[0083] In recent years, nickel and cobalt alloys because of its high wear resistance and corrosion resistance has been widely used.
Generate
Co-deposition of diamond particles containing nano-laminated nickel - cobalt alloys.
The nickel - cobalt alloy itself for corrosion
Corrosion and wear-resistant alloys.
By adjusting the electrical potential of the electrodes in the battery, it is possible to laminate the alloy group
Compounds.
By doing so, between the layers forming an electrochemical potential difference, and thus form a more
Lee corrosion and fatigue wear trend.
Also forming a crystal structure of the substrate in two separate
Special phase.
The deposition rate of diamond have also been shown to change with the current density of the battery.
[0084] Including nickel - cobalt alloy nanoscale layer, together with a diamond deposition of a multilayer coating system
Preparation, wherein the concentration of the metal changes in the adjacent layers.
[0085] As the basis for a conventional nickel bath watts bath.
The following table describes all the components of the bath.
[0086] Table 2.
Plating solution in Example
[0088] To form the sample, the steel panel was immersed in the bath and connected to a power source.
Using a computer-controlled
Software between 10mA / cm2 and 35mA / cm2 current density were adjusted to form nanoscale layers.
Is applied and the current change until a 20µm thick coating formed on the surface of the substrate.
[0089] In salf fog coating chamber were tested, as well as thin abrasion test in accordance with standard ASTMB117
Test, which shows significant wear resistance than the nickel - cobalt coating uniformity, and 316 stainless steel abrasion resistance.
[0090] Example 3
[0091] Nickel [0060] contains a special pre-preparation material - zirconium - chromium alloy systems.
[0092] Table 3. Bath preparation
[0094] Table 4. Particulate additive
[0096] Bath preparation steps:
[0097] 1. In 100 ? mixed salts, boric acid and C-Tab
[0098] 2. Make it fully dissolved, then the pH to between 5 and 6 with ammonium hydroxide to adjust
[0099] 3.Join particles and stir
[0100] 4. Before plating should be allowed in one day to make the particles are mixed surfactant adequately cover
[0101] Plating steps:
[0102] 1. Should prepare a matrix in accordance with ASTM standard
[0103] 2. Electrolyte should be maintained between 100 ? and 120 ?
[0104] 3. Solution should have sufficient stirring to prevent particle sedimentation, and the flow should be uniform across the substrate
[0105] 4. 50% duty cycle of the pulse waveform applied to the effective current 75mA / cm2 density; the average of the pulse waveform
Current density may be varied, and the change in particle contents, to form a layered control the deposition of the composition
Structure.
[0106]
[0061] In a first scanning electron microscope image, the electroplating matrix display zirconium and chromium carbide particles in the steel matrix
The combination of high-density particles.
Particle spacing <between 1 and 5 microns, and the deposition is fully dense
A.
In all throughout the deposition, the particles show a relatively uniform distribution.
The second SEM image
Shows a low particle density in the steel matrix inclusions.
Intergrain distance is between 1 and 15 microns, a
These sediments in the particle / matrix interface crack.
In the second average particle SEM images of the distribution of
Less obvious.
Two kinds of deposits shows a small amount of surface roughness.
[0107] Optional heat treatment:
[0108] [0062] In the case of coatings require a higher corrosion resistance, heat treatment may be applied, so that the included
Zirconium diffusion throughout the deposit, in which case, the formation of the corrosion-resistant NiCr metal and Zr
Between phases.
Heat through the following steps:
[0109] 1. Clean and dry the part;
[0110] 2. Using a furnace containing any atmosphere, at a rate not exceeding 10 ? / min heating the deposit until 927 ?.
[0111] 3. Held for 2 hours at 927 degrees, and
[0112] 4. The air-cooled section.
[0113] Description of the embodiments
[0063] the above method for forming nano-laminate structure is described exemplary Resistance.