rexresearch.com
Wingate A. LAMBERTSON
"E-Dam" ( WIN Cells )
Notes from Jerry Decker (KeelyNet)
Letter from Dr. Wingate Lamberson
The Cermet of Wingate Lambertson
Dr. Brian O'Leary & Stephen Kaplan : Miracle in the Void: The New Energy Revolution
Wingate Lambertson (1920-2010)
Remembering energy inventor Dr. Lambertson
US3467745 : Method of Forming Hot Pressed Refractory Carbide Bodies having Shaped Cavities
US3205465 : Thermistor assembly
CA661137 : Semi-Conductor Devices
New Energy News Vol. 6 (# 1), p. 1 (October 1966)
Wingate A. Lambertson and His WIN Cells
Win Lambertson, who has a PhD in ceramic engineering, indicates that he and his E-dam (energy-dam) technology, which he has cultivated and developed over the years, are alive and well. Win states that he has been very focused on E-dam circuits over the last 2 years, and has learned a great deal about semi-conductor switching circuits in this time frame.
The development and goal of this invention was to extract energy from the vacuum continuum and began in December, 1972. At that time, Win placed a conical shaped crystal in a DC magnetic field from which energy was extracted via a coil of wire.
He borrowed a precision multimeter for his measurements and promptly fried this multimeter. (Win recalls that he has blown many multimeters over the years.) Work to improve the efficiency of this crystal circuit did not begin until 1976, when it was discovered that removal of the crystal resulted in only a 20 percent reduction of the total energy output. (Win states that the energy could actually be felt physically.)
Win saw no point in continuing crystal studies if it only added 20 percent to the total energy measured. Win then developed a ceramic material to convert the ultra-high frequency energy of the vacuum to a lower frequency energy easily handled by conventional electronic circuits.
Since that time, a metal has been added to the ceramic making it a 'cermet', but the original concept of this material has remained the same, which concept is to collect energy from the vacuum, store it in the cermet, and then release it to a load for utlization. The term E-dam was coined to reflect this concept.
It was originally surmised that the energy for the E-dams was coming from the aether. Later, it was assumed to be coming from neutrinos. This hypothesis was then changed to one in which the 3 degree Kelvin background radiation of the universe was the source.
His current theory is that the energy photons emerging from the vacuum continuum. In other words, Win has come full circle back to his original aether theory as the source for the energy of the E-dams.
The original crystal circuit slowly began to evolve. Initially, the two electromagnets in the original circuit were replaced with two bar magnets and then these bar magnets were eventually eliminated.
The voltages evolved from initially 15 volts DC up to a maximum of 15,000 volts DC. A spark gap was added to develop high current, high voltage spikes. At 15,000 volts, Win began to observe in his garage one summer small, blue electric arcs moving across his work bench surface. These were as much as three feet long.
After that observation, the voltage was reduced because of the danger of sharing his working surface with the high voltage arcs. A resistance was also added to the circuit to slow down the electric charge across the arc. Neighbors from a block away were making snide comments about the noise.
After reviewers charged that the resistor measurements were in error because of phase angle changes, the load was changed to many 100 watt incandescent lamps in parallel, following the example of Dr. T.H. Moray.
Even with 100 lamps in parallel, the lamps would burn out. (100 lamps X 100 Watts each = 10,000 Watts) These lamps were then replaced with 100 ohm wire wound resistors. These resistors too would burn out, but it was difficult to know when they had failed. The next change was to go to industrial eight foot fluorescent lamps which lasted less than a week. His present load is a bank of 400 watt H.I.D. mercury lamps, and these have held up well.
The spark gap switching was abandoned and the change was made to a MOSFET switching system. This has since been upgraded to the use of high current IGBT's. In May of 1994, Win Lambertson presented his results to date on his E-dam circuits at the 2nd ISNE (International Symposium on New Energy) conference. For this symposium, Win had calculated a 965 percent over-unity efficiency.
Later in the summer of 1994, independent testing was conducted by two electrical engineers, Toby Grotz and Robert Emmerich, on a similar circuit utilizing solid state switching and E-dams, which were made to Win Lambertson's specifications.
This testing resulted in the identification of an anomaly in the test setup, which anomaly was unassociated with the E-dams.
Subsequent studies by Toby Grotz into 1995 of other circuit variables yielded a better understanding of the anomaly. Later, in 1996, Toby Grotz applied for an SBIR (Small Business Innovation Research) grant from the DOE (Department of Energy) to further research and develop a product based on this anomalous phenomena.
At the start of 1994 and before the 2nd ISNE conference, Win was using MOSFETs to switch voltages less than 500 volts in his E-dam circuits. Today, with the assistance of Walter Rosenthal, Win has changed over to IGBTs which can switch at voltages up to 1700 volts DC and with currents above 30 amperes.
Win states that he expects to sell his invention later this year and begin working on the history of the WIN (World into Neutrinos) process around which this invention is based.
Notes from Jerry Decker (KeelyNet)
I had the good fortune to attend the 2nd ISNE conference and meet Dr. Lambertson. He hosted a workshop where he passed around a sample of the cells. I examined it closely, it looked like a thin Oreo cookie with one wire attached to each outside cermet and a very thin rubbery material between the two cermets that looked like RTV silicone.
I speculated to Dr. Lambertson that it could be that he used ground up quartz or other crystals mixed with the RTV and secreted between the two cermet discs. Thus by shock exciting the cermets, a combined piezoelectric discharge might yield more energy than it took to produce the shock. Dr. Lamberson said he'd rather not discuss this as he was in process of filing a patent.
Also at the conference it was discussed how the 100 watt tungsten filament light bulbs he'd been using kept blowing out and his wife was upset because he kept using them up. The cause was believed to be the crystal nature of the tungsten metal which would fracture and break the filament under the impress of the high energy discharges being extracted from the aether.
Many of these cells were stacked into columns to increase the overall power output. The excess energy would come from the coupling of high intensity, short duration electrical discharges with the ambient aether/zpe field.
He was a very nice fellow and shared more information about his discovery than most inventors do, however it is now 2001 and below is an article from the Space Energy Association newsletter on September 2000 that you might find of additional interest.
August 9th, 2000
To: Friends of WIN energy
From: Win Lambertson
Subject: Load Study
Introduction ~
In my May, 2000 Progress Report I told how I came to understand the lack of certification of my method. The problem lay in the electrical measurements that were unable to measure radiant energy output when no current was moving through the tank circuit. The solution seemed simple enough. I would substitute a non-inductive resistance for the lamp load.
Load Description ~
For the past eight years my load has consisted of 400-watt H.I.D. mercury lamps. I started with four in series and gradually dropped down to one. The major problem that this load has given me has been its change in resistance with power input. Figure 1 shows a plot of ohms resistance versus watts.
The hypothesis of my method is that zero-point energy, ZPE, is collected through the acceleration of an electron charge. The highest rate of acceleration is achieved with the lowest resistance.
In a normal series of experiments I would collect data at 0.5, 1.0 and 1.5 DC amperes input. My highest yields were always found using the lowest current. If the current were much lower than 0.5 amperes the arc would quench and terminate the experiment.
The method utilizes a pulsating DC current that shows up as an alternating current on a digital multimeter. It shows up on the oscilloscope as a series of square waves. This results from the IGBT switching system that operates in either the fully closed or fully open position.
Electrons are knocked out of the mercury vapor atoms to form ions and the electrons fall back into the ions to form atoms when the switch opens. Falling back into their orbital results in the emission of light photons that are measured using 12 photocells mounted around the outside of the lamp in a light box.
Energy is collected from the vacuum on the electrical charge as it moves through a collector called an 'E-dam' after the hydro-electric dam analogy. It was evident that more light came from the lamp in an alternating current than in a direct current.
Therefore, it was possible to calibrate the photocells using a direct current. In the most recent certification attempt, a low resistance E-dam was used and it was found that the lamp was collecting ZPE without any contribution from the E-dam. This action was confirmed in an independent study by Toby Grotz. He estimated that the total gas discharge ballast market of 275 million units per year could be replaced and cut the power consumption in half.
My goal is to utilize vacuum energy in all energy applications, not just in lighting, so I had to study energy collection in a different type load. A non-inductive resistance load seemed to be a simple substitute. Energy is lost as heat and heat is generated only when the charge is moving through the load.
Radio Shack 8 ohm, 20-watt non-inductive resistors were used to make up the load. These were mounted in eight sets of three in parallel. The total array had a resistance of 24 ohms with a 480 watt capability. The resistance versus power input curve is shown in Figure 2 (not shown on my source material).
A total of eight thermistors were mounted in series on the resistor surfaces with one on each cell. These are calibrated using a DC current, allowing enough time for the surface temperature to stabilize. Instead of photocells measuring light photons, varistor temperature is utilized and measured as resistance to indicate energy being lost to the garage air.
E-dam Design ~
It was clear from my lamp studies that I had to go up in E-dam resistance in order to collect energy from the vacuum. A new design was developed based on a pyramid shaped crystal as shown in Figure 3. This goes back to some early information collected in 1973. The crystal shown was an attempt to start with a 1/4" base, optimize it and then go up in size and number of crystals to increase the power collected.
Details of the overall E-dam must be withheld in this paper in order to maximize the number of possible claims in the patent application. It is important for the reader to realize that even though the basic concept may remain the same; each final design will be different and will probably change over the years as our knowledge of materials is enhanced.
To my surprise, the change in loads did not work out as expected. The first yield was 85 percent, which of course, is impossible. This meant that some of the energy input was going through the load without doing any work. Adjusting the circuit brought it up to 116 percent before I stopped my bench work to write this paper. The next few days are needed to prepare for making a videotape of the method.
Marketing Plan ~
Individuals interested in marketing my method have requested a videotape and certification of my method before getting into a sales negotiation. My time availability has made it necessary to do the videotape as the next step. Our son, Larry, will be here over August 14th to 19th and do the videotaping for us. All funding finders should request a copy of the videotape as soon as they need it.
Anyone who needs a certification immediately should feel free to send in his own certifier at his expense with one-week notice for scheduling. Otherwise, I will schedule my own certifier as soon as I feel that I have had enough time to optimize my circuit.
Wingate A. Lambertson, Ph.D.
August 9, 2000
http://www.xontek.com/Advanced_Technology/Alternative_Energy/Cold_Fusion/Science_of_Free_Energy-part_3_of_3.shtml
THE CERMET OF WINGATE LAMBERTSON
In Florida, Wingate Lambertson, Ph.D., lights a row of lamps in his garage using what he says is electricity taken from the energy of space. It took years for Lambertson, a former director of Kentucky's Science and Technology Commission, to overcome his academic skepticism about claims that you could get something for nothing yet energy freely available from space could be tapped for useful work.
After getting his doctorate from Rutgers University, Lambertson works for United States Steel in Chicago before going into the United States Navy. After going back to Rutgers for more postgraduate work, he joined Argonne National Laboratory, where he worked on nuclear fuel technology.
Then Lambertson discovered the large body of space-energy literature that has been written by researchers in the field. Eventually, he came to believe that something similar to an nether - the basic stuff Of the universe discussed in Chapter Could exist, and that where collected, it could be used to make electricity.
After more than two decades of research and experimentation, Lambertson is certain that space energy can be turned into a practical power source through a process he calls World Into Neutrinos (WIN). He envisions it being engineered into units that will probably be set outside the home on a small concrete pad, like central air conditioning units are now, and wired into the home's master electric switchbox. The price? About $3,000 for either sale or lease cheaper than buying or leasing a car.
The WIN Process and Cermet ~
The most important part of the WIN process is Lambertson's E-dam, and the most interesting component in the E-dam is cermet. Cermet is a heat-resistant ceramic-and-metal composite invented in 1948 and considered by NASA for rocket nozzles and jet-engine turbine blades. Lambertson, who spent almost his entire career working with advanced ceramics, is experimenting to develop the best cermet for his device. The E-dam contains a plate of cermet formed into a round spacer about three inches in diameter, sandwic hed between metal plates of the same size.
The process starts with an electrical charge basically, a stream of electrons from a standard power supply. The charge flows into the E-dam, where it is held in the cermet: "It stores electrons like a [regular] dam stores water," Lambertson says. When the dam is opened, the electrons are released. As they accelerate, the falling electrons gain energy from the space energy that is present in the E-dam. This gain in energy is what allows the device to put out more power than it takes in.
The current of electrons then flows into the device to be powered, such as a lamp, and then moves into another E-dam for recycling. Lambertson says there is no way for the process to become dangerous - if too much power were generated, the E-dams would overheat, shutting down the system.
For years, Lambertson was more interested in proving that the process gained energy than in the actual amount of energy gained, since he thought scaling up the process to higher efficiencies would be a relatively simple engineering problem. When his first of three patent applications was rejected, he saw it as a blessing because it forced him to study the space-energy literature more carefully. By the fall of 1994, he had improved the process to the point where it put out twice as much energy as it started with.
Lambertson Finds Help ~
Meanwhile, Lamberston was having a frustrating time in trying to find funding and marketing help. Responses to his proposals usually fell into one of two categories:
"This will not work, your calculations are in error."
"You get it working and free of all technical problems, and we will take it off your hands."
He learned, as have other inventors in this book, that it's a waste of time to try to convince people of the validity of one's claims when those people don't want to listen. But he did find support in 1987, when he spoke at a new-energy conference in Germany. There, he found people who saw the need for his invention and agreed to market it when the WIN process is perfected.
Lambertson says that he now has active associates in Switzerland, in addition to interest shown by the United States Navy. Three different groups have shown interest in taking over and developing the WIN method.
Wingate A. Lambertson, Ph.D. believes you can power your home on space energy. Lambertson, an inventor from Florida, has developed a device he believes will tap the energy freely available in space. After earning his doctorate from Rutgers University, Lambertson went to work for US Steel before enlisting in the Navy, where he taught explosive ordnance. After going back to Rutgers for post-graduate work he joined the Argonne National Laboratory to work on nuclear fuel technology.
Once the public learns... it will be like taking the genie out of the bottle.
Lambertson, the former director of Kentucky's Science and Technology Commission, admits that he was skeptical about space energy and that it took time for him to overcome that skepticism. He now believes, however, that space energy is real and that it can be tapped for useful purposes. He describes zero-point energy this way: "Zero-Point Energy is energy from the vacuum continuum and is responsible for gravity, inertia, the Lamb Shift and the Casimir force (1,2). It is essentially inexhaustible and has no polluting byproducts." (3)
Lambertson has been working working for over two decades on an energy collecting process he calls "World Into Neutrinos (WIN)" when he thought that neutrinos were his source. He went through three other concepts before arriving at his present acceptance of ZPE as his source. In his method, energy is collected in a device consisting of a Cermet (ceramic metal) positioned between two metal plates and called an "E-dam" after the analogy to a hydroelectric dam. A charge of electrons is cycled between the E-dam to collect the energy and a lamp load to discharge the energy. Charge acceleration results in the addition of kinetic energy from the vacuum to the charge of electrons. The research apparatus used is all solid state and has no moving parts. Cermet, Lambertson believes, is the key to the device. Lambertson begins the process by supplying an initial charge to the E-Dam where he claims that the charge is held in the Cermet: "It stores electrons like a [regular] dam stores water," Lambertson says (4). When the dam is opened, Lambertson believes that the electrons gain energy from the background zero-point energy present in the dam and that this gain in energy can be made dramatic enough to power a modern home.
Patrick G. Bailey, in a publication for the International Forum on New Science, describes the WIN device: "[Lambertson] places a semiconductor ceramic barrier with a parallel capacitance between an oscillating tank circuit and a power supply. He has included test results that indicate a power input of 84 Watt-sec producing an output of 810 Watt-sec, for an over-unity ratio of 9.6." (5) The Institute for New Energy has also tested Lambertson's WIN device, though apparently without significant result so far (6).
Lambertson and his device have not met with widespread acceptance. In his preliminary solicitation to three energy companies and nine large energy users, he received responses from only four and all were negative. He concluded that any development of his method would have to come from entrepreneurs and venture capitalists. The U.S. Navy has shown an interest, but he requires a working model before they will consider it further.
The problem, which Lambertson has had to solve, was stabilization of his E-dams that have changed between the time of his apparent energy gain and the time in which a certifier has made measurements. It took him three years to understand the chemistry of the change which was going due to the electrical charge passing through his cermet. He has had to redesign his basic composition and the cermet structure several to achieve his present design.
The best results that Lambertson has had, thus far, is a yield of 175%. He is presently making a study of simplification of his method to one E-dam and one lamp load, and he plans to build several revised models for evaluation by interested venture capital sources. He has identified at least three venture capital sources ready to invest in the new energy field of zero-point energy collection.
Lambertson is currently working on the right combination of ceramic and metal for the E-Dam to boost the performance level of his device; stating much remains to be done. He is confident that he can perfect the process and foresees a time in the future when a modern home can be powered on energy drawn freely from the zero-point energy he and others believe to be all around us in space. "Once the general public learns that it can take control over its own energy supply," Lambertson says, "it will be like taking the genie out of the bottle."
"Miracle in the Void: The New Energy Revolution"
Dr. Brian O'Leary & Stephen Kaplan
A pioneering solid-state technology is Wingate Lambertson's World into Neutrinos (WIN) process. Dr. Lambertson has conducted materials research and development for such organizations as U.S. Steel, the Universities of Toledo and Rutgers, Argonne National Laboratory, the Carborundum Company and Spindletop. He has been doing independent research over the past two decades on a a solid state device which he believes can provide a practical source of power through the harnessing of zero-point energy.3
Lamberton's "electron dam" (E-dam) is made out of Cermet, a highly advanced heat-resistant ceramic and metal composite. An accelerated electrical charge sends a stream of electrons into the E-dam, and the electrons become stored much like a conventional dam stores water. When the electrons are released, they gain energy from the zero-point energy present in the E-dam. After they flow into the unit to be powered, they move into another E-dam for recycling.
Lambertson changed his cermet chemistry and E-dam design when he learned that an unexpected chemical reaction was taking place. A different combination of materials and composite design appears to stabilize the process, and a yield of 145 percent was achieved in tests conducted in 1998. Since that time an induction effect has become a major problem which severely inhibits charge acceleration and yield. The present direction of his research is towards reducing induction in his E-dam using two different complementary approaches. It appears that these approaches will solve his remaining major problem. His highest yield using these approaches in June 1999 was 109 percent. Lambertson is confident that he will achieve higher yields with further experimentation, probably as high as 200 per cent, the level needed for commercial viability. He is currently exploring future production with interested manufacturers. Lambertson has a strong interest in providing new solutions for the energy needs of developing nations.
Highly regarded Canadian inventor John Hutchinson has developed
a solid state "crystal energy converter" made out of very common
materials which is an electrical power source he claims behaves
like a battery and never runs down. This small, self-running
power source, which typically puts out DC power amounting to one
or two volts, has produced up to six watts of power, and he
believes it could be engineered to replace batteries and other
power needs.
http://www.arc-ethic.com/wordpress/tout-les-articles/les-inventeurs-dans-lenergie/
In Florida, Dr. Wingate Lambertson light a series of bulbs, he said, the electricity energy in the room. Lambertson is a former director of the Science and Technology Commission of Kentucky, and it took him years to overcome his academic skepticism of those who claimed to be able to get something out of nothing - the energy available in space could be captured and used for practical purposes.
After over twenty years of research and experimentation, Lambertson is now sure that the energy of the space can be transformed into a working power source through a process he called the World in Neutrinos ( World Into Neutrinos = WIN). He intends to manufacture small parts, which will probably be placed on the outside of the house, on a small concrete foundation, as are air conditioners today, joined by son in the main electrical panel in homes. Their price: $ 3,000; we can buy or rent - it's cheaper than buying or leasing a car.
The most important part of the process is the WIN-E displeasure Lambertson, and most important component of E-dam is the cermet. The cermet is a composite ceramic and heat-resistant metal, invented in 1948, NASA contemplated use in nozzles of its rocket and turbine blades in jet engines. Lambertson, who spent most of his career working on advanced ceramics, is now testing what cermet be best for his camera. The E-dam contains a disc-shaped plate cermet of about 7.5 centimeters in diameter, placed between metal plates of the same size. The process begins with an electrical charge (actually an electron current) provided by a standard source of energy. The charge flows into the E-dam, where it is retained in the cermet "it stores the electrons like a dam usually holds water," says Lambertson. When the dam is opened, the electrons are released. When accelerating, the ropy electrons gaining energy through the energy of this space in the E-dam. This energy gain allows the device to release more power than it consumes. The flow of electrons then enters the object you want to run, such as a light bulb, and then enters another E-dam for a new cycle. Lambertson said that the method can never be dangerous, if the energy was too large, the E-dams overheat and would stop the system.
For years Lambertson was more interested in proving that the process is capable of obtaining energy, rather than how much energy was won, because he thought the adaptation process to higher yields was a relatively simple technical problem. When the first of three patent applications was rejected, he finally took very good because it forced him to look more closely bibliographies energy space. In fall 1994, he improved the process to the point that it produced two times more energy than it consumes.
http://changingpower.net/remembering-energy-inventor-dr-lambertson/
At the end of July my next bimonthly column – this time honoring Dr. Wingate Lambertson — will be published in Atlantis Rising magazine. He died recently, mere weeks before his 90th birthday. His wife Eileen passed on earlier this year. They had chosen Florida for most of their retirement years, so his final month was also shadowed by news of oil drifting toward familiar beaches.
Seeing the possibility of a new energy source, Dr. Lambertson had wanted to bring clean energy and jobs to replace coal mining in his home state of Kentucky.
But he didn’t ever get the funding that could have hired a team of specialists to help him refine and further develop his solid-state “zero-point energy” converter. (He named the method — which was based on acceleration of electron charges — the World into Neutrinos (WIN) process.) At the end of this lifetime he had a dream telling him that in the year 2018 his process would finally be ready for use by the world. Before his daughter told me about that dream, I wondered why I decided to write my Report from the Front column about an invention whose inventor didn’t live to see it vindicated.
Then I received confidential information from another scientist, whose very recent small-scale but precise experiments, done in collaboration with a colleague, “prove that a ‘field’ exists in space which can do work on a mechanical system to increase its kinetic energy when acceleration is present.”
The cautious experimenter speculated: “Possibly, this field is a consequence of the ether Einstein alluded to in 1920.” (A patent is pending on the device used in this new experiment, so no more will be said about it at this time.)
Coincidentally, acceleration (in Dr. Lambertson’s case it was acceleration of electron charges) was the vital part of both experiments, including the un-named device tested this month. Acceleration was the factor that Win Lambertson believed enabled his WIN system to tap into the background energy of space and therefore added excess energy to the output of his system.
He wasn’t a stereotypical garage inventor. Instead, he was a former executive director of Kentucky’s Science and Technology Commission who overcome his academic skepticism about extraordinary claims that energy freely available from space could be tapped for useful work.
Following are excerpts from what his daughter wrote:
Wingate Augustus Lambertson, Ph.D., 89, of Lexington, Kentucky, departed this earth on May 10, 2010 at St. Joseph Hospital.
Mr. Lambertson attended Rutgers University where he received his masters and Ph.D. in Ceramic Engineering. While at Rutgers, he invented a ceramic coating for boiler-furnace refractories for use by the Navy. This invention proved to add substantially to boiler life for the Navy fleet and was very important to the sea-keeping ability of the fleet.
Dr. Lambertson left Rutgers to work in Chicago at the Argonne National Laboratories. While there, he worked on refractory problem involved in atomic energy. He then went to Toledo, Ohio, to teach at Toledo University. Next he went to Grand Island, NY to work at Carborundum. In 1963 he moved his family to Lexington, KY to work at Spindletop Research where he once again was doing research.
He retired to Florida in 1980 where he could devote all his time to his energy research, specifically Zero Point Energy, ZPE. He was a dreamer beyond his time and very late in life still believed that there is a very viable energy source out there and believed that it will come to fruition in 2018. He continued reading and writing right up to the end of his very active life.
A memorial was held on Thursday, May 13, 2010 in Lexington, KY and his ashes are buried next to his beloved wife of 63 years who passed away on January 25, 2010.
The following is adapted from my earlier book, The Coming Energy Revolution (Avery Publishing Group, 1996, now out of print):
THE CERMET OF WINGATE LAMBERTSON
In Florida, Wingate Lambertson, Ph.D., lights a row of lamps in his garage using what he says is electricity taken from the energy of space. It took years for Lambertson, a former director of Kentucky’s Science and Technology Commission, to overcome his academic skepticism about claims that you could get something for nothing yet energy freely available from space could be tapped for useful work.
After getting his doctorate from Rutgers University, Lambertson worked for United States Steel in Chicago before going into the United States Navy. After going back to Rutgers for more postgraduate work, he joined Argonne National Laboratory, where he worked on nuclear fuel technology.
Then Lambertson discovered the large body of space-energy literature that has been written by researchers in the field. Eventually, he came to believe that something similar to an aether – the basic stuff of the universe — could exist, and that where collected, it could be used to make electricity.
After decades of research and experimentation, Lambertson was certain that space energy can be turned into a practical power source through a process he called World Into Neutrinos (WIN). He envisioned it being engineered into units that will probably be set outside the home on a small concrete pad, like central air conditioning units are now, and wired into the home’s master electric switchbox. The price? Cheaper than buying or leasing a modestly-priced car.
The most important part of the WIN process was Lambertson’s E-dam, and the most interesting component in the E-dam was cermet. Cermet is a heat-resistant ceramic-and-metal composite invented in 1948 and considered by NASA for rocket nozzles and jet-engine turbine blades. Lambertson, who spent almost his entire career working with advanced ceramics, experimented to develop the best cermet for his device. The E-dam contains a plate of cermet formed into a round spacer about three inches in diameter, sandwiched between metal plates of the same size.
The process starts with an electrical charge, a stream of electrons from a standard power supply. The charge flows into the E-dam, where it is held in the cermet: “It stores electrons like a regular dam stores water,” Lambertson said. When the dam is opened, the electrons are released. As they accelerate, the falling electrons gain energy from the space energy that is present in the E-dam. This gain in energy is what allows the device to put out more power than it takes in.
The current of electrons then flows into the device to be powered, such as a lamp, and then moves into another E-dam for recycling. Lambertson said there is no way for the process to become dangerous – if too much power were generated, the E-dams would overheat, shutting down the system.
For years, Lambertson was more interested in proving that the process gained energy than in the actual amount of energy gained, since he thought scaling up the process to higher efficiencies would be a relatively simple engineering problem. When his first of three patent applications was rejected, he saw it as a blessing because it forced him to study the space-energy literature more carefully. Eventually, he improved the process to the point where it put out twice as much energy as it started with, but he still needed to perfect it into a reliable product.
(Keep in mind, that chapter excerpt was written in 1994-5.)
US3467745 / CA838015
This invention relates to improvements in hot pressing refractory carbide bodies, and more particularly to a new and improved method of forming hot pressed refractory carbide bodies having shaped cavities.
A primary object of the present invention is to form a hot pressed refractory carbide body having a shaped cavity by filling the oversize cavity in the oversize body with a water-reactive carbide forming or 10 containing mixture and by heating such body above the reactive carbide forming temperature prior to hot pressing to size and shape.
Following such hot pressing, the mixture is readily removed by reacting the reactive carbide with water, thereby leaving a cavity of the desired size and shape in the hot pressed refractory carbide body.
Additional objects and advantages of the invention will become apparent upon consideration of the following detailed description and accompanying drawings, wherein:
Fig. 1 is a fragmentary sectional view of an oversize cup-shaped refractory carbide body having an oversize cavity filled with a water -20 reactive carbide forming or containing mixture and placed in a mold prior to the hot pressing operation;
Fig. 2 is a view similar to Fig. 1, but following the hot pressing operation;
Fig. 3 is a sectional view of the hot pressed, cup-shaped body having a shaped cavity following removal of the filling;
Fig. 4 is a fragmentary sectional view similar to Fig. 1, but showing an oversize serrated refractory carbide body having oversize cavities filled with a water-reactive carbide forming or containing mixture and placed in a mold prior to the hot pressing operation. 30 Fig. 5 is a view similar to Fig. 4, but following the hot pressing operation; and
Fig. 6 is a sectional view of the hot pressed serrated body having shaped cavities following removal of the filling.
Referring to Figs. 1-3, which are generally to scale, the inventive method is shown as applied to forming a cup-shaped, hot pressed refractory carbide body having a shaped cavity in accordance with the following example.
EXAMPLE 1
239.3 grams of niobium carbide having a particle size of -325 mesh was mixed with 15 cc of a 10 percent polyvinyl alcohol solution and cold pressed to form an oversize cup-shaped, cylindrical body 10 having the following approximate dimensions: an outer diameter of 10 1-5/8 inches, an inner diameter of 1-1/8 inches, an overall length of 3 inches and a bottom wall thickness of l/2 inch, and being provided with an oversize cavity 12. After drying, body 10 was placed in a cylindrical graphite mold 14 having opposed plungers 16, 18 and its cavity 12 was filled with a water-reactive carbide containing mixture 20 of equal volumes of calcium carbide having a particle size range of +60 -40 mesh and 20 grams of amorphous carbon having a particle size range of +600 -325 mesh. Body 10 was heated in an induction furnace (not shown) under argon and no applied positive mechanical pressure until the temperature reached 1000°C. At this 20 point, while the heating continued, the plungers 16, 18 were actuated by suitable means (not shown) to maintain contact pressure with body 10 and which pressure was gradually increased from 1400°C to a maximum of 3000 pounds per square inch at the hot pressing temperature of 2000°C. This maximum pressure was held at 2000°C for 20 minutes until the hot pressing operation was completed, with the total time of the run being 80 minutes. The furnace was shut off and the pressure released during cooling.
As shown in Fig. 2, the hot pressed refractory carbide body 100 was reduced to the desired size and shape, having about the same outer 30 and inner diameters as body 10, but a reduced length of about 1-1/2
inches, and a reduced bottom wall thickness of about l/4 inch. At the same time, the cavity 120 was also reduced to the desired size and shape, while the hot pressed mixture 200 continued to fill cavity 120.
When body 100 had cooled sufficiently to permit handling, it was removed from mold 14, and immersed in water. Thereupon, the entire mixture was readily removed by reaction between the calcium carbide and the water, leaving the hot pressed body 100 and cavity 120 of the desired size and shape, as shown in Fig. 3.
Referring to Figs. 4-6, which are generally to scale, but enlarged in the horizontal direction to more clearly illustrate structural details, the inventive method is shown as applied to forming a serrated hot pressed refractory carbide body having shaped cavities or serra-10 tions in accordance with the following examples.
EXAMPLE 2
Fifty grams of niobium carbide having a particle size of -325 mesh was loaded into a cylindrical graphite mold 22 having an internal diameter of 1 inch and oppositely disposed plungers 24, 26. This was lightly compressed to form circular bottom layer 28a of oversize body 28. Then, a 1 inch wide sheet metal divider (not shown) was set on edge .into the mold touching the layer 28a. One side was loaded with 12.5 grams of the niobium carbide and the other side with an equal volume of a water-reactive carbide containing mixture, both sides being 20 lightly compressed to the same height to form semi-circular layers 28b of body 28 and 30a of the mixture filling lower oversize cavity 32a of the body. The water-reactive carbide containing mixture was composed of, by volume, 25 percent calcium carbide having a particle size range of +60 -40 mesh and 75 percent amorphous carbon having a particle size range of +600 -325 mesh.
Another, intermediate circular layer 28c of 50 grams of niobium carbide was loaded and compressed above the divided layers 28b, 30a, followed by loading and compressing of corresponding divided layers 28d, 30b and the final or top layer 28e corresponding to layers 28a and 28c. 30 Thus, the oversize serrated refractory carbide body 28 was completed to have the following approximate dimensions, an outer diameter of 1 inch, an overall height of 3-1/2 inches and three circular layers 28a, 28c, 28e each 5/6 inch thick and separated by two oversize cavities 32a, 32b each 1/2 inch thick and filled with layers 30a, 30b respectively of the water-reactive carbide containing mixture.
Body 28 was heated in an induction furnace (not shown) under argon and only contact pressure by plungers 24, 26 up to the hot pressing temperature of 1500°C. At this temperature, the plungers 24, 26 were actuated to increase the positively applied mechanical pressure to the maximum of 1000 pounds per square inch, which was held for 20 minutes until the hot pressing operation was completed, with the total time of the run being 77 minutes. At this point, the furnace was shut off and 10 the pressure released during cooling.
As shown in Fig. 5, the resulting hot pressed refractory carbide body 280 was reduced to the desired size and shape, having the same outer diameter as body 28, but a shorter length of about 2-5/8 inches, the thickness of layers 280a, 280c, and 280e being reduced to about 5/8 inch each, and the thickness of cavities 320a, 320b and layers 280b, 280d being reduced to about 3/8 inch each, with the hot pressed mixture of layers 300a and 300b filling cavities 320a, 320b.
When body 280 had cooled sufficiently to permit handling, it was removed from mold 22 and immersed in water. Within 10 minutes, most 20 of the moderate and steady reaction between the water-reactive carbide and the water was completed permitting ready removal of layers 300a, 300b. It was noted that while C2H2 was evolving during the reaction, it literally "kicked" the excess carbon out into the water, thereby assisting in ejection of the layers 300a, 300b from cavities 320a, 320b respectively. When removed from the water, the hot pressed body 280 and cavities 320a, 320b were: of the desired size and shape, as shown in Fig. 6.
EXAMPLE 3
Example 2 was repeated, except that the water-reactive carbide 30 containing mixture of layers 30a, 30b was composed of, by volume,
10 percent aluminum carbide having a particle size of -200 mesh and 90 percent carbon. Actually a combination, by volume, of 75 percent aluminum carbide and 25 percent graphitic carbon having a particle size of -200 mesh was mixed with enough amorphous carbon having a particle size range of +600 -325 mesh to provide the aforesaid mixture.
Following completion of the 68 minute run and cooling, body 280 was immersed in water, as before. While the reaction was slow, it was steady, and eventually layers 300a and 300b disintegrated and dropped out leaving a serrated body of the desired size and shape.
EXAMPLE 4
Example 2 was repeated, except that the water-reactive carbide forming mixture of layers 30a, 30b was composed of, by volume, 6.5 10 percent aluminum having a particle size of 270 mesh and 93.5 percent amorphous carbon having a particle size range of +600 -325 mesh. The purpose of this mixture was to produce a partially converted mixture during firing of, by volume, 10 percent aluminum carbide and 90 percent carbon.
Following the 80 minute run and cooling, body 280 was immersed in water with immediate reaction. Although the reaction was slow, it was steady, and eventually layers 300a and 300b disintegrated and dropped out, leaving a serrated body of the desired shape.
From the foregoing, it is now evident how the invention 20 accomplishes the desired results and numerous advantages of the invention likewise are apparent. While the inventive method has been described and illustrated herein by reference to certain preferred embodiments, it is to be understood that various changes and modifications may be made therein by those skilled in the art without departing from the inventive concept, the scope of which is to be determined by the appended claims.
For example, while niobium carbide was used in the examples, the inventive method is equally applicable to hot pressing various refractory carbides such as ZrC, HfC, SiC, TaC, and B^C. Likewise, a water-reactive 30 carbide forming mixture composed of calcium said carbon could be used in the inventive method, provided calcium of sufficiently small particle size, on the order of about -200 mesh is employed and care is taken to prevent oxidation.
Also published as:
GB990417 / NL267879
PATENT SPECIFICATION
Semi-conductor Devices We, THE CARBORUNDUM COMPANY, of Niagara Falls, in the County of Niagara and State of New York, United States of America, a Gorporation organized and existing under the laws of the State of Delaware, United States of America, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: -
THIS INVENTION RELATES TO electrical resistance bodies, and more particularly to thermistor assemblies.
A thermistor, as the term is employed herein, is an electrical resistance body having a high sensitivity to changes in temperature over a wide temperature range. Thus its electrical resistance is sensitive to change with changes in temperature. Thermistors which decrease in resistivity with increase in temperature are said to have a negative temperature coefficient of resistivity.
Thermistors are widely employed in temperature measuring and controlling devices and their uses have grown very rapidly in recent years. Among present uses of thermistors are included replacements for thermocouples, especially for use at moderate temperatures up to about 600 F. In this application they offer several advantages over thermocouples, since they are more sensitive to temperature change than thermocouples.
Furthermore, thermocouples produce a relatively weak signal which must be amplified to actuate controlling circuits, whereas thermistors are adapted to actuate relays directly, thereby minimizing the cost of control equipment. Thermistors are also used to compensate for changes in amBient temperature in order to maintain the accuracy of electrical measuring equipment over wide ranges of _ ambient temperature. Thermistors are also useful in time-delay applications.
An object of the present invention is to provide improved thermistor assemblies.
According to the present invention, there is provided a thermistor assembly, comprising a single crystal of pure silicon carbide or silicon carbide modified by the presence throughout the body thereof of an element selected from Groups IIIA and VA of the periodic chart, and electrical leads joined by high temperature fusion respectively to isolated areas of said crystal.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing in which:Figure 1 is a perspective view of a thermistor assembly made in accordance with the present invention; and Figure 2 is a top plan view of an operating device embodying the thermistor of Figure 1.
In accordance with the present invention a selected silicon carbide, in the form of a single crystal, is positioned between at least two electrically-conductive leads and in contact therewith. The parts are then secured in relationship to each other as by the spring tension of the leads and thereafter subjected to a temperature sufficient to fuse the leads to contact points of the crystal. The fusion is preferably performed in a protective atmosphere such as argon, helium, hydrogen or vacuum to avoid oxidation of the leads and the silicon carbide.
The fusion can be effected in two different ways. In one method of fusion, which has been employed in the present invention, the electrical leads are Tieated by their inherent resistance by passing an electrical current therethrough to bring them to fusion temperature for a sufficient interval of time to If effect the fusion and joining. As an alternative of this method, a heating circuit can be established from a source of current through one lead, thence through the crystal, back through the other lead, and to the source of current.
In a second method, the entire assembly is placed in a furnace and raised to a temperature at which the fusion will be effected.
As will be seen in the drawings, thermistor assemblies of the present invention include a single crystal 10 of silicon carbide which is positioned between two electrical leads 11.
The parts are assembled and held in fixed relationship to each other and heated to fusion temperature by one of the methods hereinbefore described to join the electrical leads to isolated points of the crystal. As shown in Figure 1, a globule of ceramic or porcelain cement 12 is thereafter placed on either side of the crystal 10, in surrounding relationship to the electrical leads and is allowed to harden to hold the parts in fixed, assembled relationship, and to strengthen the assembly.
An operating device, made in accordance with the present invention is illustrated in Figure 2. As shown in this latter figure, the crystal I0 of silicon carbide is fused between two isolated electrical leads 11 which are supported on either side of the crystal by globules of ceramic cement 12. The terminal ends 13 of the electrical leads are exposed to the atmosphere, beyond the ceramic cement. However, the other ends of the electrical leads extend into a twin conduit porcelain insulator 14 which can be a part of a probe assembly, of which the thermistor assembly forms a part.
Silicon carbide crystals applicable to use in the present invention include the following 5 types:
1. Intrinsic. This designation relates to theoretically pure silicon carbide. Intrinsic silicon carbide would provide a high resistivity material with a very high sensitivity to temperature changes. It would have a B value of 27,600 K.
The B value or characteristic is a measure of the sensitivity of the resistance of the body to temperature change over a given range of temperature. It is calculated from the formula 2.303 log R, R2 B1 1 T, T2 wherein R1 equals the resistance in ohms at temperature (T,) and R2 equals the resistance in ohms at temperature (To) and T, and T2 are temperatures in degrees Kelvin.
2. Compensated. This designation relates to silicon catrbide having P-type and N-type impurities consisting of elements of groups IIA and VA of the periodic table in balanced amounts, in trace quantities of only a few parts per million. Compensated silicon carbide may have a resistivity from about 100 ohmcm, to 10 ohm-cm, at room temperature, depending upon how well compensated the particular material happens to be. Commercial colourless silicon carbide is a typical compensated material and has a B value of about 2000 K. Commercial colourless crystals are obtained by selecting them from commercial green crude silicon carbide.
3. P-type. This designation relates to silicon carbide characterised by electrical conduction by positive charge carriers. The positive charge carriers are pictured as the absence of electrons (holes). A P-type semiconductor contains a small but effective amount of trivalent impurity namely elements from group IliA of the periodic chart, which cause impurity semiconduction by motion of positive electrical charge carriers. These include boron, aluminium and gallium in trace amounts.
Commercial black silicon carbide contains P-type crystals which usually have a room temperature electrical resistivity in the range from about 0.1 to about 1 ohm-cm., depending upon the concentration of impurity.
P-type gilicon carbide crystals having an impurity level sufficiently high to impart a resistivity of about 10 ohm-cm. could be quite useful as a high wattage thermistor.
In the P-type materials, aluminium and boron can provide B values of about 2500 K.
4. N-type. This designation relates to silicon carbide in which electrical conduction occurs by motion of negative charge carriers.
The resistivity is low, being in the range 100 from about 0.01 to 0.1 ohm-cm., and it is characterized by low sensitivity to thermal change.
Commercial green silicon carbide contains N-type crystals, the presence of nitrogen 105 therein in trace amounts contributing N-type characteristics. A B value of about 1250 K is provided by nitrogen.
Phosphorus and arsenic in trace amounts also contribute N-type characteristics. Thus 110 the N-type materials include nitrogen, phosphorus or arsen'ic, representing Group VA of the periodic chart of the elements.
N-type silicon carbide would be quite useful as a thermistor for very low temperature 115 indications in the vicinity of the temperature of liquid oxygen. The low resistivity and the low temperature sensitivity of resistivity of N-type silicon carbide would be an advantage in this range. P-type and N-type silicon 123) carbide, of the 5 materials contemplated for use in the present invention, are of the lowest resistivity, and the resistivity will depend upon the concentration of impurities, 990,417 990,417 However, a given amount of impurities of the P-type silicon carbide would be higher in resistivity than the same amount of impurities of the N-type silicon carbide. Likewise the temperature sensitivity of resistivity for the P-type material would be higher than that for the N-type material.
5. Boron solid solution with silicon carbide. This material is readily distinguishable from P-type silicon carbide. The Ptype silicon carbide containing boron is lower in resistivity, the boron level being in the range below 0.01% by weight. However, the solid solution of boron in silicon carbide, boron content above about 1% by weight, shows an increase in resistivity due to the distortion of the silicon carbide lattice.
The crystals of boron solid solution with silicon carbide are obviously different from normal silicon carbide crystals; they have a definite fish scale appearance, whereas, silicon carbide crystals show definite formations of hexagonal crystal faces. There is also a definite shift in the X-ray diffraction lines produced from the crystals of boron solid solution with silicon carbide. This is proof that the normal silicon carbide crystal lattice has been distorted and the spacing between individual atoms has been changed.
The crystals of boron solid solution with silicon carbide can be formed by two methods.
In one method, silicon carbide is recrystallized in the presence of boron. In the other method the crystals are formed directly from a mix containing silicon carbide-formning ingredients, namely SiO, and carbon, and a desired amount of boron.
Thermistors made in accordance with the present invention, from boron solid solutions with silicon carbide have generally displayed B values in the range from about 1200 K. to about 1800 K.
A thermistor of boron solid solution with silicon carbide is advantageous because the electrical properties are not sensitive to minor fluctuations of boron content. For example, when boron in the range from about 1 to about 10% by weight is added to the mix before the crystals are formed by recrystallization, there is very little difference 'in the resistivity of the resultant crystals at room temperature. A boron content from about 1 to about 3% by weight is provided by the above additions of boron.
The following specific examples illustrate and highlight the present invention.
EXAMPLE I
A pair of tungsten lead Wires approximately 0.005 inch in diameter were supported at their ends by spot welding to the ends of larger diameter nickel wires and a crystal of compensated silicon carbide approximately 0.05 inch square by 0.01 inch thick was positioned therebetween with the opposite major surfaces of the crystal contacting the leads. The crystal was held by the spring tension of the leads.
Thereafter alternating current at 2.5 amperes and 6-8 volts was run through the leads until they were heated to a temperature of about 1950 C., which was maintained for a period of about 5 seconds to weld the leads to the crystal. The assembly was then cooled and globules of ceramic cement were applied to the lead wires adjacent the crystal to strengthen the assembly.
The thermistor so produced had a B value of 1860 K.
EXAMPLE II
A pair of tungsten lead wires approximately 0.005 inch in diameter were supported at their ends by spot welding to the ends of larger diameter nickel wires and a crystal of boron solid solution with silicon carbide containing about 3% by weight of boron, approximately 0.05 inch square by 0.01 inch thick was positioned therebetween with the opposite major surfaces of the crystal contacting the leads. The crystal was held by the spring tension of the leads.
Thereafter alternating current at 2.5 amps and 6-8 volts was run through the leads until they were heated to a temperature of about 1950 C., which was maintained for a period of about 5 seconds to weld the leads to the crystal. The assembly was then cooled and globules of ceramic cement were applied to the lead wires adjacent the crystal to strengthen the assembly.
The thermistor so produced had a B value of 1500 K.
The amount of the Groups liIA and VA elements to be included within silicon carbide crystals for use in the present invention will be in the range of a significant amount up to about 5% by weight of the crystal.
Electrical leads adapted to use in the present invention are of a selected number.
It has been found that those made of substantially pure tungsten and substantially pure tantalum are preferred. However, it is to be included within the scope of the invention to utilize leads made of tungstentantalum alloys and of alloys of tungsten and tantalum with other alloying metals.
Rhenium, molybdenum and iridium can also be employed. Other metals such as iron, cobalt, nickel, rhodium and platinum can be used. However, when the latter metals are used, some free silicon should be added at the interface, otherwise a graphite layer tends to form at the interface between the metal and the crysal which weakens the bond.
The lead wires can be placed on opposite faces of the crystal to form a thermistor, and this is a convenient way to form the device. Also the lead wires can be attached to opposite edges of the crystals or to isolated areas on one face of the crystal. In forming the thermistor, the crystal is preferably supported between leads by the spring tension of the leads so that no extraneous supporting structure is present to contaminate the finished thermistor.
CA661137
This invention relates to electrical resistance bodies, and more particularly to thermistor assemblies including a single crystal of a silicon carbide»
A thermistor, as the term is employed herein, is an electrical resistance body having a high sensitivity to changes in temperature over a wide temperature range. Thus its electrical resistance is sensitive to change with changes in temperature. Thermistors which decrease in resistivity with increase in temperature are said to have a negative temperature coefficient of resistivity.
Thermistors are widely employed in temperature measuring and controlling devices and their uses have grown very rapidly in recent years. Among present uses of thermistors are included replacements for thermocouples, especially for use at moderate temperatures up to about 600°F, In this application they offer several advantages over thermocouples, since they are more sensitive to temperature change than thermocouples. Furthermore, thermocouples produce a relatively weak signal which must be amplified to actuate controlling circuits, whereas thermistors are adapted to actuate relays directly, thereby minimizing the cost of control equipment. Thermistors are also used to compensate for changes in ambient temperature in order to maintain the accurancy of electrical measuring equipment over wide ranges of ambient temperature. Thermistors are also useful in time-delay applications.
It is an important object of the present invention to provide novel thermistor assemblies.
A further object is to provide thermistor assemblies made of a single crystal of pure silicon carbide or of a selected silicon carbide characterized by the presence throughout the body thereof of an element from Groups IIIA and VA of the period chart.
A further object is to provide a thermistor assembly made up of a silicon carbide crystal and having electrical leads joined to isolated points of said crystal by high temperature fusion only#
These and other objects and advantages accruing from the invention will become more apparent from the following description and the accompanying drawings, wherein
In accordance with the present invention a selected silicon carbide, in the form of a single crystal, is positioned between at least two electrically-conductive leads and in contact therewith. The parts are then secured in relationship to each other as by the spring tension of the leads and thereafter subjected to a temperature sufficient to fuse the leads to contact point s of the crystal. The fusion is preferably performed in a protective atmosphere such as argon, helium, hydrogen or vacuum to avoid oxidation of the leads and the silicon carbide.
The fusion can be effected in two different ways. In one method of fusion, which has been employed in the present invention, the electrical leads are heated by their inherent resistance by passing an electrical current therethrough to bring them to fusion temperature for a sufficient interval of time to effect the fusion and joinder. As an alternative of this method, a heating circuit can be established from a source of current through one lead, thence through the crystal, back through the other lead, and to the source of current.
In a second method, the entii*e assembly is placed in a furnace and raised to a temperature at which the fusion will be effected.
As will be seen in the drawings, thermistor assemblies of thé present invention include a single crystal 10 of silicon carbide which is positioned between two electrical leads 11. The parts are assembled and held in fixed relationship to each other and heated to fusion temperature by one of the methods hereinbefore described to join the electrical leads to isolated points of the crystal. As shown in Pig. 1, a globule of ceramic or porcelain cement 12 is thereafter placed on either side of the crystal 10, in surrounding relationship to the electrical leads and is allowed to harden to hold the parts in fixed, assembled relationship, and to strengthen the assembly.
An operating device, made in accordance with the present invention is illustrated in Pig. 2, As shown in this latter figure, the crystal 10 of silicon carbide is fused between two isolated electrical leads 11 which are supported on either side of the crystal by globules of ceramic cement 12. The terminal ends 13 of the electrical leads are exposed to the atmosphere, beyond the ceramic cement. However, the other ends of the electrical leads extend into a twin conduit porcelain insulator 11+ which can be a part of a probe assembly of which the thermistor assembly forms a part.
Silicon carbide crystals applicable to use in the present invention include the following 5 types:
1, Intrinsic. This designation relates to theoretically pure silicon carbide. Intrinsic silicon carbide would provide a high resistivity material with a very high sensitivity to temperature changes. It would have a B value of 27,600°K.
The B value or characteristic is a measure of the sensitivity of the resistance of the body to temperature change over a given range of temperature. It is calculated from the formula
2.303 log Rj
B = 1-1 . T ^2
wherein R^ equals the resistance in ohms at temperature (T^) and Rg equals the resistance in ohms at temperature (T^) and T^ and Tg are temperatures in degrees Kelvin,
2, Compensated. This designation relates to silicon carbide having P-type and N-type impurities in balanced amounts, in trace quantities of only a few parts per million. Compensated silicon carbide may have a resistivity from about 100 ohm-cm. to 10^ ohm-cm. at room temperature, depending upon how well compensated the particular material happens to be. Commercial colorless silicon carbide is a typical compensated material and has a B value of about 2000°K. Commercial colorless crystals are obtained by selecting them from commercial green crude silicon carbide.
3. P-type. This designation relates to silicon carbide characterized by electrical conduction by positive charge carriers. The positive charge carriers are pictured as the absence of electrons (holes). A P-type semiconductor contains a small but effective amount of trivalent impurity such as elements from column IIIA of the periodic chart, which cause impurity semiconduction by motion of positive electrical charge carriers. These include boron, aluminum and gallium in trace amounts.
Commercial black silicon carbide contains P-type crystals which usually have a room temperature electrical resistivity in the range from about 0.1 to about 1 ohm-cm., depending upon the concentration of impurity.
P-type silicon carbide crystals having an impurity level sufficiently high to impart a resistivity of about 10 ohm-cm, could be quite useful as a high wattage thermistor. i
In the P-type materials, aluminum and boron provide B values of about 2j?00 K.
]+. N-type. This designation relates to silicon carbide in which electrical conduction occurs by motion of negative charge carriers. The resistivity is low, being in the range from about 0,01 to 0.1 ohm-cm., and it is characterized by low sensitivity to thermal change.
Commercial green silicon carbide contains N-type crystals, the presence of nitrogen therein in trace amounts contributing N-type characteristics, A B value of about 1250°K, is provided by nitrogen.
Phosphorus^nd arsenic in trace amounts also contribute N-type characteristics. Thus the N-type materials include nitrogen, phosphorus and arsenic, representing Group VA of the periodic chart of the elements.
N-type silicon carbide would be quite useful as a thermistor for very low temperature indications in the vicinity of the temperature of liquid oxygen. The low resistivity and the low temperature sensitivity of resistivity of N-type silicon carbide would be an advantage in this range, P-type and N-type silicon carbide, of the $ materials contemplated for use in the present invention, are of the lowest resistivity, and the resistivity will depend upon the concentration of impurities. However, the same amounts of impurities of the P-type silicon carbide would be higher in resistivity than the N-type silicon carbide. Likewise the temperature sensitivity of resistivity for the P-type material would be higher than that for the N-type material.
5, Boron solid solution with silicon carbide.
This material is readily distinguishable from P-type silicon carbide. The P-type silicon carbide containing boron is lower in resitivity, the boron level being in the range below 0.01$. However, the solid solution of boron in silicon carbide, boron content above about 1shows an increase in resistivity due to the distortion of the silicon carbide lattice.
The crystals of boron solid solution with silicon carbide are obviously different from normal silicon carbide crystals; they have a definite fish scale appearance, whereas, silicon carbide crystals show definite formations of hexagonal crystal faces. There is also a definite shift in the X-ray diffraction lines produced from the crystals of boron solid solution with silicon carbide. This is proof that the normal silicon carbide crystal lattice has been distorted and the spacing between individual atoms bas been changed.
The crystals of boron solid solution with silicon carbide can be formed by two methods. In one method, silicon carbide is recrystallized in the presence of boron. In the other method the crystals are formed directly from a mix containing silicon carbide-forming ingredients, namely SiC^ and carbon, and a desired amount of boron.
Thermistors made in accordance with the present invention, from boron solid solutions with silicon carbide have generally displayed B values in the range from about 1200°K. to about l800°K.
A thermistor of boron solid solution with silicon carbide is advantageous because the electrical properties are not sensitive to minor fluctuations of boron content. For example, when boron in the range from about 1 to about 10$ is added to the mix before the crystals are formed by reorystallization, there is verly little difference in the resistivity of the resultant crystals at room temperature, A boron content from about 1 to about 2>f° by weight is provided by the above additions of boron.
The following specific examples illustrate and highlight the present invention.
EXAMPLE I
A pair of tungsten lead wires approximately 0.005 inch in diameter were supported at their ends by spot welding to the ends of larger diameter nickel "wires and a crystal of compensated silicon carbide approximately 0.05 inch square by 0.01 inch thick was positioned therebetween with the opposite major surfaces of the crystal contacting the leads. The crystal was held by the spring tension of the leads.
Thereafter alternating current at 2,5 amperes and i
6-8 volts was run through the leads until they were heated i to a temperature of about 1950GC,, which was maintained for a period of about 5 seconds to weld the leads to the crystal. The assembly was then cooled and globules of ceramic cement were applied to the lead wires adjacent the crystal to strengthen the assembly.
The thermistor so produced had a B value of 1860°K,
EXAMPLE II
A pair of tungsten lead wires approximately 0*005 inch in diameter were supported at their ends by spot welding to the ends of larger diameter nickel wires and a crystal of boron solid solution with silicon carbide containing about yfo by weight of boron, approximately 0,05 inch square by 0,01 inch thick was positioned therebetween with the opposite major surfaces of the crystal contacting the leads. The crystal was held by the spring tension of the leads.
Thereafter alternating current at 2,5 amps and 6-8 volts was run through the leads until they were heated to a temperature of about 1950°C,, which was maintained for a period of about 5 seconds to weld the leads to thecrystal. The assembly was then cooled and globule* of ceramic cement were applied to the lead wires adjacent the crystal to strengthen, the assembly.
The thermistor so produced had a B value of 1500°K.
The amount of the Groups IIIA and VA elements to be Included within siltoon carbide crystals of the present invention will be in the range of a significant amount of up to about 5$ by weight of the crystal.
Electrical leads adapted to use In the present invention are of a selected number. It has been found that those made of substantially pure tungsten and substantially pure tantalum are preferred. However, it is to be included Within the scope of the invention to utilize leads made of j tungsten-tantalum alloys and of alloys of tungsten and tanta-j lum with other alloying metals. Rhenium, molybdenum and iridium are also definite possibilities. Other metals such as iron, cobalt, nickel, rhodium and platinum can be used. However, when the lattër metals are used, some free silicon should be added at the interface, otherwise a graphite layer tends to form at the interface between the metal and the crystal which weakens the bond.
The lead wires can be placed on opposite faces of the crystal to form a thermistor, and this is a conveniènt way to form the device. Also the lead wires can be attached to opposite edges of the crystals or to isolated points on one face of the crystal. In forming the thermistor, the crystal is preferably supported between leads by the spring tension of the leads so that no extraneous supporting |structure is present to contaminate the finished thermistor»
While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.