Of Carbon (i.e., Silicon Carbide) Patents (Class 423/345)
-
Patent number: 5571758Abstract: A process for preparing a material includes preparing a preform having carbon particles and a carrier material. A first end of a wick, made of a material that is wetted by liquid silicon, is contacted to the preform. The wick and the preform are heated to a temperature greater than the melting point of silicon, so that silicon flows along the wick to the preform. The silicon reacts with the carbon particles to form silicon carbide. At least a portion of the reaction of carbon and silicon is performed in an atmosphere containing a source of nitrogen and substantially free of oxygen, so that free silicon reacts to form silicon nitride.Type: GrantFiled: December 19, 1994Date of Patent: November 5, 1996Assignee: General Electric CompanyInventor: Theodore R. Grossman
-
Patent number: 5525556Abstract: Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.Type: GrantFiled: June 7, 1995Date of Patent: June 11, 1996Assignee: The Dow Chemical CompanyInventors: Stephen D. Dunmead, Alan W. Weimer, Daniel F. Carroll, Glenn A. Eisman, Gene A. Cochran, David W. Susnitzky, Donald R. Beaman, Kevin J. Nilsen
-
Patent number: 5465184Abstract: Silicon carbide is produced by chemical vapor deposition at temperatures from 1340.degree.-1380.degree. C., deposition chamber pressures of 180-200 torr, H.sub.2 /methyltrichlorosilane ratio of 4-10 and deposition rate of 1-2 .mu.m/min. Furthermore, H.sub.2 supplied as a part of the gas stream contains less than about 1 part per million (ppm) O.sub.2 gas, and various means are provided to exclude particulate material from the deposition chamber. The silicon carbide is polishable to <5 .ANG. RMS as measured on a Talystep mechanical profiler and has a thermal conductivity of at least about 300 W/mk. The silicon carbide is particularly suitable for applications where high polishability and thermal conductivity is desired, such as hard disc drives and read/write heads of head-disc assemblies, and also optical apparatus which require a very high polish.Type: GrantFiled: November 17, 1994Date of Patent: November 7, 1995Assignee: CVD, IncorporatedInventors: Michael A. Pickering, Jitendra S. Goela, Lee E. Burns
-
Patent number: 5462800Abstract: A silicon carbide coated carbon matrix/carbon fiber composite material is provided. The carbon composite base material, coated with silicon carbide, comprises a siliconized layer and a non-siliconized layer. The siliconized layer comprises silicon carbide matrix and non-siliconized carbon fibers. The siliconized layer also has a non-planar interface with a series of elongated protrusions penetrating into the surface the of non-siliconized layer. A gas-permeable intermediate coating formed on the carbon composite material can help produce such a siliconized layer.Type: GrantFiled: December 20, 1993Date of Patent: October 31, 1995Assignee: Toshiba Ceramics Co.Inventors: Hiraku Yamazaki, Teruo Sugai, Shigeo Kato, Haruo Tazoe, Shiroh Hotate, Iwao Goto
-
Patent number: 5460759Abstract: The disclosure teaches a method for obtaining porous solids of refractory carbide with a large specific surface area. An exclusively organic, polymeric and/or copolymerizable compound, for example a resin, which can be coked and to provide a solid carbon skeleton, is mixed with a powder of metal, or metalloid, or a compound thereof which can be reduced by carbon. The mixture is shaped, the organic compound is cross-linked or hardened, and the compound is heat treated from 500.degree. to 1000.degree. C. to coke it, then heat treated to carburize it.Type: GrantFiled: June 16, 1994Date of Patent: October 24, 1995Assignee: Pechiney RechercheInventor: Dominique Dubots
-
Patent number: 5455212Abstract: A method for producing alumina-silicon carbide ceramic powders by in situ production of silicon carbide particles by introducing a pyrolyzable carbon source, preferably a gaseous hydrocarbon, into a reactor containing an alumino-silicate, pyrolyzing the pyrolyzable carbon source to form carbon particles in situ, wherein the carbon particles are capable of reacting with a silicate in the alumino-silicate to form carbide products, and then reacting the silicate and the carbon particles in situ at an effective temperature, preferably at least 1450.degree. C. and more preferably at least 1500.degree. C., for a sufficient time to transform the alumino-silicate and the pyrolyzable carbon source into the composite ceramic powder having alumina (Al.sub.2 O.sub.3) and silicon carbide (SiC) as major phases.Type: GrantFiled: March 15, 1994Date of Patent: October 3, 1995Assignee: The University of British ColumbiaInventors: Asoke C. Das Chaklader, Edmond C. Y. Lin
-
Patent number: 5449654Abstract: The invention concerns a process for preparing a silicon carbide foam consisting of attacking a polyurethane foam with an alkaline solution, impregnating it, after rinsing and drying, with a suspension of silicon powder in an organic resin, heating progressively to polymerise the resin, carbonising the polyurethane foam and resin, and finally carburising the silicon contained in the resin suspension by means of the carbon originating from the carbonisation of the foam and resin.The foams obtained are characterised by a high microporosity and a mesoporosity which is variable according to the carburising temperature.The invention finds an application in the manufacture of catalyst carriers for exhaust chambers and filters for diesel engines.Type: GrantFiled: March 13, 1995Date of Patent: September 12, 1995Assignee: Pechiney RechercheInventors: Marie Prin, Gerard Baluais
-
Patent number: 5441799Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 3-25 vol % are prepared from raw batches containing a multimodal distribution of silicon carbide particles and comprised of at least a first set of particles having one average grain size and a second set of particles having another average grain size larger than the first set of particles. The resulting pores are 3-5 microns in the largest dimension, with an aspect ratio between about 1/1 and about 3/1 . The porous bodies, e.g., in the form of mechanical seal members, exhibit good tribological properties.Type: GrantFiled: January 4, 1994Date of Patent: August 15, 1995Assignee: The Carborundum CompanyInventors: Dean P. Owens, Irving B. Ruppel
-
Patent number: 5429780Abstract: A process for preparing a silicon carbide foam by impregnating a polyurethane foam with a suspension of silicon powder in an organic resin, heating progressively to polymerize the resin, heating further to carbonize the polyurethane foam and resin, and finally further heating to carburize the silicon contained in the resin suspension by means of carbon obtained from the carbonization of the foam and resin. The foam obtained is characterized by high macroporosity and a mesoporosity which is variable according to the carburizing temperature.Type: GrantFiled: April 28, 1994Date of Patent: July 4, 1995Assignee: Pechiney RechercheInventors: Marie Prin, Geard Baluais
-
Patent number: 5427761Abstract: A process for the production of a metal carbide having a BET specific surface area of 10 to 200 m.sup.2 /g, in which a reaction mixture including carbon having a specific surface area of at least 200 m.sup.2 /g and a compound of the metal to be reacted with the carbon which is volatile at 900.degree. C. to 1400.degree. C. is introduced into a reactor, the reactor is scavenged by a flow of inert gas and the reaction mixture is heated under the flow of inert gas at 900.degree. to 1400.degree. C. for a time sufficient to volatilize the metal, reduce the volatilized metal compound to the metal with and carburize the metal by reaction with carbon, forming the metal carbide. The metal carbide formed is cooled under the flow of inert gas.Type: GrantFiled: November 19, 1992Date of Patent: June 27, 1995Assignee: Pechiney RechercheInventors: Bernard Grindatto, Alex Jourdan, Marie Prin
-
Patent number: 5407750Abstract: A high purity and high density silicon carbide sintered body is made by controlling an amount of aluminum in an aluminum compound as a sintering additive from more than the solid solution upper limit in silicon carbide, preferably, as aluminum from 0.4 to 0.7% by weight of the total silicon carbide and aluminum compound. The sintered body has a density of 99.9% or more and can have a smooth surface with an average surface roughness of 2 nm or less when polished. Thus, this sintered body is suitable for producing a precise, rigid and heat resistant mirror substrate.Type: GrantFiled: December 18, 1992Date of Patent: April 18, 1995Assignee: Nippon Steel CorporationInventors: Toshiya Kinoshita, Hiroshi Kubo
-
Patent number: 5391524Abstract: A method of producing heavy metal carbides of high specific surface area characterised in that a compound in the gazeous state of said heavy metal is caused to react with reactive carbon having a specific surface area at least equal to 200 m.sup.2.g.sup.-1 at a temperature comprised between 900.degree. and 1400.degree. C., and thus obtained carbides.Type: GrantFiled: January 7, 1993Date of Patent: February 21, 1995Assignee: Pechiney ElectrometallurgieInventors: Marc-Jacques Ledoux, Jean-Louis Guille, Cuong Pham-Huu, Sophie Marin
-
Patent number: 5383421Abstract: Beta-silicon carbide whiskers of superior uniformity can be formed, either singly or in-situ in a matrix, by heating a source for silicon with a source of carbon (greater than 0 percent but less than or equal to about 60 percent of stoichiometric, with respect to the silicon source) in the presence of a titanium-containing catalyst, such as titanocene dichloride. Advantageously, the titanium catalyst can be applied by drying a solution of the titanium catalyst on the carbon and silicon sources. The titanium, carbon and silicon sources are then heated together, preferably to between about 1800.degree. C. and about 1850.degree. C., resulting in a product containing high quality beta-silicon carbide whiskers.Type: GrantFiled: May 19, 1993Date of Patent: January 24, 1995Assignee: The Dow Chemical CompanyInventors: Stephen D. Dunmead, Kevin E. Howard
-
Patent number: 5380511Abstract: A process for producing silicon carbide-base complex is disclosed. In the process of this invention, a silicon carbide-base complex is produced by means of depositing carbon produced by means of pyrolysis of a gas comprising a hydrocarbon or a hydrocarbon halide on a porous synthesized silica glass body. As a result, the process of manufacture according to the present invention is capable of producing a high purity and a high strength silicon carbide-base material, which is useful as a jig for producing semiconductors, for example, a heat resistance jig material such as a process tube for wafer boats used for heat doping operation.Type: GrantFiled: July 12, 1993Date of Patent: January 10, 1995Assignee: Sumitomo Metal Industries, Ltd.Inventors: Tadahisa Arahori, Shigetoshi Hayashi, Kazuhiro Minagawa
-
Patent number: 5370854Abstract: Carbothermally reduce a metal oxide to its corresponding metal nitride or metal carbide powder in a vertical gravity flow reactor by adding precursor pellets containing the metal oxide, a thermally decomposed binder material and carbon or a source of carbon directly to a heated reaction zone within the reactor. The pellets form a pellet bed, the top of which must be maintained within the heated reaction zone. The binder material is a blend of wheat and corn starches, optionally in conjunction with another binder such as melamine. The binder material thermally decomposes to a carbonaceous residue which functions both as an additional source of carbon and as a binder for the precursor pellets. The reactor may be modified by adding an internal vent line to remove volatile materials from the heated reaction zone before they have an opportunity to condense on internal reactor surfaces.Type: GrantFiled: January 8, 1993Date of Patent: December 6, 1994Assignee: The Dow Chemical CompanyInventors: John P. Henley, Gene A. Cochran, David A. Dunn, Glenn A. Eisman, Alan W. Weimer
-
Patent number: 5366941Abstract: A composite ceramic material that is stable and shows a high strength in the temperature range of room temperature to 1600.degree. C. as well as has a toughness high-enough to be used as structural material and a process for producing it are provided. This composite ceramic material is composed of a matrix substantially made up of Si.sub.3 N.sub.4 and Si.sub.2 N.sub.2 O and a dispersion phase substantially made up of SiC where the matrix contains 0.05% by weight or less of metal element impurities such as Al, Ca and Fe. SiC grains or fibers are dispersed in the dense matrix made up of Si.sub.3 N.sub.4 and Si.sub.2 N.sub.2 O fine grains, which are substantially free from element impurities except Si, C and O. According to one aspect of this invention, this ceramic material is produced by Si.sub.3 N.sub.4 with SiO.sub.2 to form matrix powders that contain 0.Type: GrantFiled: October 13, 1992Date of Patent: November 22, 1994Assignee: NGK Insulators, Ltd.Inventors: Tomonori Takahashi, Manabu Isomura
-
Patent number: 5366713Abstract: A method of forming p-type silicon carbide which comprises using reactive source gases comprising silane, hydrogen, trimethylboron, and either diborane or boron trifluoride, to thereby attain a widened band gap by the action of the carbon contained in the trimethylboron.Type: GrantFiled: May 28, 1993Date of Patent: November 22, 1994Assignee: Showa Shell Sekiyu K.K.Inventors: Porponth Sichanugrist, Tetsuro Nii, Takahisa Kase
-
Patent number: 5348718Abstract: A method and apparatus are provided for producing a product comprising a carbide compound, such as for example silicon carbide. A reactor is provided which has a chamber defined therein which is divided into a combustion zone and a reaction zone. A combustible mixture is injected into the combustion zone in a direction generally toward the reaction zone, and is accordingly combusted in the combustion zone. At least one reactant (i.e. silane) is injected at the boundary between the zones into the reactor chamber in a direction generally parallel to the longitudinal axis of the chamber so as to react to form raw product comprising the carbide compound.Type: GrantFiled: April 4, 1990Date of Patent: September 20, 1994Assignee: Phillips Petroleum CompanyInventors: Michael C. Carter, Bruce W. Gerhold
-
Patent number: 5342502Abstract: A method for preparing silicon carbide particles dispersed in an electrolytic bath for composite electroplating of metals includes the steps of washing the silicon carbide particles with an organic solvent; washing the silicon carbide particles with an inorganic acid; grinding the silicon carbide particles; and heating the silicon carbide particles in a nickel-containing solution at a boiling temperature for a predetermined period of time.Type: GrantFiled: October 21, 1993Date of Patent: August 30, 1994Assignee: Industrial Technology Research InstituteInventors: Yu-Min Peng, Jih-Wen Wang, Chun-Ying Liue, Shinn-Horng Yeh
-
Patent number: 5324494Abstract: A method is described for producing silicon carbide particles using a silicon source material and a hydrocarbon. The method is efficient and is characterized by high yield. Finely divided silicon source material is contacted with hydrocarbon at a temperature of 400.degree. C. to 1000.degree. C. where the hydrocarbon pyrolyzes and coats the particles with carbon. The particles are then heated to 1100.degree. C. to 1600.degree. C. to cause a reaction between the ingredients to form silicon carbide of very small particle size. No grinding of silicon carbide is required to obtain small particles. The method may be carried out as a batch process or as a continuous process.Type: GrantFiled: January 21, 1993Date of Patent: June 28, 1994Assignee: Midwest Research InstituteInventor: Gregory C. Glatzmaier
-
Patent number: 5322822Abstract: Ultra-high-strength refractory silicon carbide fiber having a decomposition temperature of not less than about 1800K, a breaking strength of not less than about 5 GPa, and a modulus of elasticity of not less than about 300 GPa is disclosed, which is obtained by irradiating a precursor comprising organosilicon compound fiber with an ionizing radiation in a mixed carrier gas comprising a reactive gas and a first inert gas to render the precursor infusible and calcining the irradiated precursor in a second inert gas. Irradiation damage can be minimized, and no oxygen is incorporated into the fiber.Type: GrantFiled: November 4, 1992Date of Patent: June 21, 1994Assignee: Japan Atomic Energy Research InstituteInventors: Tadao Seguchi, Noboru Kasai, Kiyohito Okamura, Masaki Sugimoto, Tsuyoshi Mitsuhashi
-
Patent number: 5318761Abstract: A process for the preparation of a beta-silicon carbide powder of high purity which is suitable for use in the manufacture of semiconductor equipment and which has a content of 1 ppm or less of each atom harmful to the manufacture of semiconductor devices. The process comprises preparing a carbon- and silicon-containing starting mixture comprising (a) at least one siliceous material selected from liquid silicon compounds and solid siliceous substances derived from a hydrolyzable silicon compound, and (b) at least one carbonaceous material selected from polymerizable or cross-linkable organic compounds prepared in the presence of a catalyst which is substantially free from atoms harmful to the manufacture of semiconductor devices. The starting mixture comprises at least one liquid substance used as component (a) or (b). The starting mixture is then solidified by heating and/or by use of a catalyst or a curing agent.Type: GrantFiled: July 17, 1992Date of Patent: June 7, 1994Assignees: Sumitomo Metal Industries, Ltd., Bridgestone CorporationInventors: Shoichi Kojima, Kazuhiro Minagawa, Tasuku Saito, Tasuo Kurachi, Haruyuki Kano
-
Patent number: 5298467Abstract: A binder-containing granulated silicon carbide products for the manufacture of highly dense silicon carbide ceramic products and the SiC ceramic products which can be made from the novel granulated silicon carbide products, especially highly dense SiC high-performance pressurelessly sintered ceramics.Type: GrantFiled: August 12, 1992Date of Patent: March 29, 1994Assignee: Solvay Deutschland GmbHInventors: Antonio M. Hurtado, Hans R. Dose, Zeynel Alkan, Wolfgang Habel, Christoph Nover, Hans Meyer
-
Patent number: 5288444Abstract: Ceramic fibers formed by the pyrolysis of organosilicon preceramic polymers are provided with increased resistivity by treating the fibers in air at temperatures of less than 1,000.degree. C. to oxidize the free carbon content of the fibers.Type: GrantFiled: April 17, 1987Date of Patent: February 22, 1994Assignee: Hoechst Celanese Corp.Inventors: Harris A. Goldberg, Ilmar L. Kalnin, Clyde C. Williams
-
Patent number: 5283044Abstract: A super heat-resistant silicon carbide fiber has an oxygen content of less than 0.1% by weight. In a process for producing the super heat-resistant silicon carbide fiber, a precursor fiber prepared by spinning a polycarbosilane having an oxygen content of less than 0.8% by weight is irradiated with a radiation in an oxygen-free atmosphere or in vacuo to make the precursor fiber infusible. The infusibilized fiber is fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C. without exposure to an oxidizing atmosphere; or stabilized in the same atmosphere at a temperature of from 300.degree. to 600.degree. C. without exposure to an oxidizing atmosphere and fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C.Type: GrantFiled: November 25, 1991Date of Patent: February 1, 1994Assignees: Japan Atomic Energy Research Institute, Nippon Carbon Co., Ltd.Inventors: Kiyohito Okamura, Hiroshi Ichikawa, Michio Takeda, Tadao Seguchi, Noboru Kasai, Masanobu Nishii
-
Patent number: 5265118Abstract: A silicon carbide whisker production apparatus manufactured by placing a plurality of lidded reaction vessels in the longitudinal direction of an Acheson furnace at intervals, packing graphite grains in the gaps between the adjacent reaction vessels and around the reaction vessels along the longitudinal direction of the furnace starting with the furnace-side ends of terminal electrodes to form a surrounding heating zone, and packing a heat insulating packing around the surrounding heating zone.Type: GrantFiled: March 18, 1992Date of Patent: November 23, 1993Assignee: Tokai Carbon Co., Ltd.Inventors: Takashi Takenaka, Shigeto Mori, Osamu Machida
-
Patent number: 5262235Abstract: A ceramic fiber is provided with a plurality of coatings to define a system useful in making composite articles in the manufacture of which the fiber experiences applied stress such as thermal shock. For example, such applied stress occurs in molten metal spraying about fibers to provide a metal matrix composite. The fiber, as a core, is provided with a first coating layer tightly bonded to a lateral surface of the fiber and has a first structure. A second coating layer is then deposited on the first layer and has a second structure different from the first structure thereby defining an interface between the coating layers which is a debonding discontinuity zone sufficiently weak to enable reparation of the layers as a result of applied stress, such as introduced by a thermal shock experience.Type: GrantFiled: October 28, 1991Date of Patent: November 16, 1993Assignee: General Electric CompanyInventor: Joseph A. Heaney, III
-
Patent number: 5258170Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of carbon from a source containing less than 0.2% by weight of iron, with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere in the presence of 0.2-10% by weight of an oxide or oxide precursor of Ca, Mg, Al, W, Ce or Cu; 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, and preferably 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less. The carbon is preferably in the form of particles of less than 50 .mu.m and the silica or precursor is preferably in the form of particles of less than about 45 .mu.m. The weight ratio of silica to carbon is greater than 1.76:1. The carbon source is preferably a pure form of carbon, e.g. graphite or amorphous carbon.Type: GrantFiled: July 15, 1991Date of Patent: November 2, 1993Assignee: Alcan International LimitedInventor: Luc Parent
-
Patent number: 5256448Abstract: Method of making a coherent film of silicon carbide on a surface, comprising forming a solution in the solvent of from 0.05 to 0.3 moles alkoxy silicon per mole of water, the solution also containing an acid catalyst and a carbonaceous material in the ratio 1 to 3 moles carbon per mole of silicon. Hydrolysis is allowed to occur followed by removal of volatile material after hydrolysis at this or an earlier stage; applying the solution to the surface; and thereafter heating at at least 1300.degree. C. The solvent comprises 0.3 to 1 mole of acetone per mole of water.Type: GrantFiled: October 11, 1991Date of Patent: October 26, 1993Assignee: British Technology Group Ltd.Inventor: Luiz D. De Castro
-
Patent number: 5252766Abstract: There is disclosed a method for producing a polysilane which comprises reacting a hydrosilane compound in the presence of an organolanthanoid complex.Type: GrantFiled: September 13, 1991Date of Patent: October 12, 1993Assignee: Director-General of Agency of Industrial ScienceInventors: Toshiyasu Sakakura, Masato Tanaka, Toshiaki Kobayashi
-
Patent number: 5248483Abstract: An apparatus and methods are provided for producing ceramic products in a reactor so as to minimize deposits therein. The reactor has a chamber defined therein which is divided into a combustion zone, into which a combustible mixture is injected, and a reaction zone in which the ceramic product is produced from at least one reactant injected into the chamber at the boundary between the zones. At least a portion of the wall defining the reaction zone is surrounded by at least one passageway through which coolant fluid is passed during ceramic production. Either carbide product or nitride product can be produced in the reaction zone according to the invention.Type: GrantFiled: March 28, 1991Date of Patent: September 28, 1993Assignee: Phillips Petroleum CompanyInventor: Michael C. Carter
-
Patent number: 5234675Abstract: An organosilicon high molecular compound having a skeleton of silicon and carbon or a compound obtained by polymerization of an organometallic compound and the organosilicon high molecular compound is melted into a fiber, then the fiber is antimelt-treated in an oxidizing atmosphere, and the antimelt-treated yarns are thereafter heated in an atmosphere of inert gas to obtain a fiber of silicon carbide containing 2 to 20% by volume of oxygen. This fiber is further sintered in an atmosphere of inert gas at a temperature of 1400 to 2100 deg. C. and a pressure of 300 to 3000 kg/cm.sup.2. A sintered body of silicon carbide having an excellent bending strength is obtained without the use of a sintering agent or a binder. A fiber of silicon carbide having a predetermined oxygen content and a thin amorphous carbon layer thereon is obtained from the starting fiber by antimelt-treating and then heating in an atmosphere of a mixture of an inert gas and a hydrocarbon gas.Type: GrantFiled: October 1, 1991Date of Patent: August 10, 1993Assignee: Nippon Carbon Co. Ltd.Inventors: Hiroshi Ichikawa, Yoshikazu Imai
-
Patent number: 5234674Abstract: A process for the recovery of metal carbides from ferroalloys and nickel alloys of niobium, tantalum, vanadium, and hydrides thereof is disclosed. The selected ferroalloy or nickel alloy is contacted with a hydrogen containing gas, subdivided, and carbided by contact with a hydrocarbon containing gas at a temperature above 500.degree. C. The carbided reaction product is then leached with an aqueous acid solution for recovery.Type: GrantFiled: June 27, 1991Date of Patent: August 10, 1993Assignee: Teledyne Industries, Inc.Inventor: James A. Sommers
-
Patent number: 5232951Abstract: A continuous flow method and system is provided for converting environmentally pollutant by-product waste gases emitted during the manufacture of silicon carbide in a first manufacturing plant to methanol in a second manufacturing plant such that release of the gases into the atmosphere may be prevented.Type: GrantFiled: January 21, 1992Date of Patent: August 3, 1993Assignees: Exolon-ESK Company, Elektroschmelzwerk Kempten GmbHInventors: Hans Pfingstl, Walter Martyniuk, Armand Ladage, Tom McNally, Robert Myers, Ludwig Eberle
-
Patent number: 5229468Abstract: A block copolymer is prepared by reacting an aluminum-nitrogen polymer and a silazane polymer at a temperature not greater than 400.degree. C. Block copolymers containing alkenyl or alkynyl groups can be crosslinked by supplying energy to generate free radicals. An AlN/SiC containing ceramic is formed by pyrolyzing the crosslinked block copolymer in a nonoxidizing atmosphere.Type: GrantFiled: February 13, 1992Date of Patent: July 20, 1993Assignee: Hercules IncorporatedInventor: James A. Jensen
-
Patent number: 5221526Abstract: A process for producing silicon carbide whiskers in which a particulate form of carbon is combined with a silicon component, a boron component and seeding component to form a mixture which is then subjected to temperatures above about 1300.degree. C. in a nonoxidizing atmosphere such that carbon reacts with silica to form silicon carbide whiskers. The preferred particulate carbon, silicon component, boron component and seeding component are, respectively, carbon black, fumed silica, boron oxide and cobalt, iron or nickel. The size and shape of the whiskers can be controlled by varying the size of the seeding component and the concentration of the boron component.Type: GrantFiled: May 24, 1991Date of Patent: June 22, 1993Assignee: Advanced Industrial MaterialsInventors: Dongxin Qi, Roy T. Coyle, Richard D. Tait, Rick J. Orth
-
Patent number: 5202105Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: July 5, 1990Date of Patent: April 13, 1993Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
-
Patent number: 5190737Abstract: A process for preparing silicon carbide by carbothermal reduction which includes transporting, in a gaseous medium, a particulate reactive mixture of a silica source and a carbon source through a reaction zone. The heating rate of the atmosphere within the reaction zone is such that substantially all of the reactive mixture is heated at a heating rate of at least about 100.degree. C./second until an elevated temperature of at least 1800.degree. C. is reached. Either (1) carbon monoxide is added to the reaction zone or (2) a carbon monoxide level in the reaction is achieved in order to provide at least about 30 mole percent of the gases exiting the reaction zone to achieve a higher yield of silicon carbide.Type: GrantFiled: April 30, 1991Date of Patent: March 2, 1993Assignee: The Dow Chemical CompanyInventors: Alan W. Weimer, Raymond P. Roach, John P. Henley
-
Patent number: 5178847Abstract: The invention relates to a process for the production of silicon ceramic whiskers and silicon ceramic powder from silicon fluoride and ammonia or a hydrocarbon, at an elevated temperature. According to the invention, the hydrocarbon or ammonia (4) is decomposed separately at a high temperature into reactive carbon or nitrogen and hydrogen, whereafter the carbon or nitrogen radical thus obtained is further in a gas phase contacted with reactive silicon formed therein from silicon difluoride, in order to deposit finely-divided silicon nitride or silicon carbide out from the gas phase.Type: GrantFiled: November 28, 1989Date of Patent: January 12, 1993Assignee: Kemira OYInventors: Vesa-Pekka Judin, Hayha, Pertti Koukkari
-
Patent number: 5173283Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of a non-graphitizable form of hard carbon containing 0.5-1.5% by weight of aluminum and at least 0.2% by weight of iron (preferably anthracite coal, most preferably Pennsylvania anthracite), with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere. If the carbon contains 0.2-1.0% by weight of iron, 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, is added (if not already present). In the invention, 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less are added to the reaction mixture to control the size of the platelets so that a majority have a size of less than 20 .mu.m. The carbon is in the form of particles of less than 50 .mu.Type: GrantFiled: February 4, 1992Date of Patent: December 22, 1992Assignee: Alcan International LimitedInventor: Luc Parent
-
Patent number: 5171722Abstract: A method of preparing preceramic SiC fibers having a very low oxygen content by forming fibers from a solution of a polycarbosilane and a vinylic SiC precursor in a mutual volatile solvent, heating fibers in an oxygen-free inert atmosphere to effect a cross-linking reaction therebetween. Also disclosed is a method of preparing SiC fibers having superior high temperature properties and a very low oxygen content comprising heating the above-described cross-linked preceramic fibers in an inert atmosphere substantially free of oxygen for a time and at a temperature sufficient to pyrolyze the cross-linked fibers to SiC fibers. The disclosure also describes the novel fibers produced by the above-described methods.Type: GrantFiled: October 9, 1991Date of Patent: December 15, 1992Assignee: University of FloridaInventors: William Toreki, Christopher D. Batich
-
Patent number: 5168014Abstract: A silicon carbide-reinforced light alloy composite material comprises a matrix of a light weight alloy and a reinforcing material consisting of at least one of a silicon carbide whisker and a silicon carbide grain. In the composite material, the content of SiO.sub.2 contained in the reinforcing material, is set in the range of 0.05 to 5.0% by weight.Type: GrantFiled: October 23, 1989Date of Patent: December 1, 1992Assignee: Honda Giken Kogyo Kabushiki KaishaInventors: Akimasa Daimaru, Tohru Ohta, Tatsuya Suzuki, Masao Ichikawa, Hirotaka Koshitani, Hideyuki Fujishiro
-
Titanium nitride coated silicon carbide materials with an interlayer resistant to carbon-diffusivity
Patent number: 5167943Abstract: Finely divided silicon carbide materials, particularly powders, whiskers and short fibers, are provided with a titanium nitride surface coating by the process of (i) placing a low carbon diffusivity layer atop the silicon carbon, (ii) placing a titanium metal coating atop the low carbon diffusivity layer, and (iii) nitriding the titanium metal.Type: GrantFiled: December 17, 1990Date of Patent: December 1, 1992Assignee: Norton CompanyInventors: Shih-Yee Kuo, Hyun-Sam Cho, Jeffrey D. Bright -
Patent number: 5164345Abstract: The processes of the invention involve the formation of an initial reactant mixture by combining sources of SiO.sub.2, B.sub.2 O.sub.3, aluminum, and carbon. The mixture may then optionally be shaped or compacted. The reactant mixture is then heated to start a reaction which is described by the formula:4 C+3 SiO.sub.2 +2 B.sub.2 O.sub.3 +8 Al.fwdarw.4 Al.sub.2 O.sub.3 +B.sub.4 C+3 SiC.Depending on the actual reactant mixture compositions and reaction conditions, other reactions may also occur.Type: GrantFiled: March 21, 1991Date of Patent: November 17, 1992Assignee: W.R. Grace & Co.-Conn.Inventors: Roy W. Rice, Leonard E. Dolhert, Jack H. Enloe
-
Patent number: 5162269Abstract: This invention relates to the preparation of thermally stable, substantially polycrystalline silicon carbide ceramic fibers derived from a polycarbosilane resin. The unexpected thermal stability of these fibers is achieved by the incorporation of boron prior to ceramification.Type: GrantFiled: July 15, 1991Date of Patent: November 10, 1992Assignee: Dow Corning CorporationInventors: David C. Deleeuw, Jonathan Lipowitz, Paul P. Lu
-
Patent number: 5128115Abstract: A method is described for producing silicon carbide particles using solar energy. The method is efficient and avoids the need for use of electrical energy to heat the reactants. Finely divided silica and carbon are admixed and placed in a solar-heated reaction chamber for a time sufficient to cause a reaction between the ingredients to form silicon carbide of very small particle size. No grinding of silicon carbide is required to obtain small particles. The method may be carried out as a batch process or as a continuous process.Type: GrantFiled: April 8, 1991Date of Patent: July 7, 1992Assignee: The United States of America as represented by the United States Department of EnergyInventor: Gregory C. Glatzmaier
-
Patent number: 5108729Abstract: A method and apparatus are provided for producing a product comprising a carbide compound, such as for example silicon carbide. A reactor is provided which has a chamber defined therein which is divided into a combustion zone and a reaction zone. A combustible mixture is injected into the combustion zone and accordingly combusted to form hot combustion products. At least one reactant (i.e. silane) is injected at the boundary between the zones so as to be carried into the reaction zone by the combustion products and react to form raw product comprising the carbide compound. The raw product can be purified by subsequent processing to remove oxygen and convert by-products to the desired carbide compound. The product of the invention has a low level of impurities and is made up of submicron, highly uniform particles. This makes the product particularly useful for fabrication of sintered ceramic parts.Type: GrantFiled: October 2, 1989Date of Patent: April 28, 1992Assignee: Phillips Petroleum CompanyInventors: Bruce W. Gerhold, George F. Schuette, Kenneth E. Inkrott
-
Patent number: 5102646Abstract: The invention relates to a method of fabrication in the powdered state of ceramic compounds formed between a metalloid and a refractory metal, characterized in that it involves the following steps:a) said metalloid is caused to react with a reducing metal within a liquid bath constituted at least partly by a fused salt of said reducing metal in order to obtain a saltlike intermediate compound which combines said reducing metal and the metalloid, in solution in said bath,b) a reducible salt of said refractory metal is then injected into said bath in a divided form which is directly distributed throughout the bath in order to produce said powder by reaction of the reducible salt with said intermediate compound of the reducing metal.Type: GrantFiled: April 20, 1990Date of Patent: April 7, 1992Assignee: CerexInventor: Gerard Bienvenu
-
Patent number: 5093039Abstract: Disclosed is an electrically conductive sintered silicon carbide body having an electric resistivity of not higher than 1 .OMEGA..multidot.cm, which is produced by(a) mixing(1) a first silicon carbide powder having a mean grain size of from 0.1 to 10 .mu.m with(2) a second silicon carbide powder having a mean grain size of not greater than 0.1 .mu.m prepared by(2-1) introducing a starting gas composed of a silane compound of silicon halide and a hydrocarbon into a plasma of a non-oxidative atmosphere, and(2-2) conducting gas phase reaction between the silane compound or silicon halide and the hydrocarbon while controlling the pressure of the reaction system within the range of from less than 1 atom to 0.1 torr, and(3) optionally, a carbon powder which is required for reducing oxides contained in both the first and second silicon carbide powders,(b) optionally reducing the oxides with the carbon, and(c) heating the resulting mixture for sintering. Also, processes of producing the same are disclosed.Type: GrantFiled: November 6, 1989Date of Patent: March 3, 1992Assignees: Kazunori Kijima, Sumitomo Cement Co., Ltd.Inventors: Kazunori Kijima, Eiki Arai, Youichi Miyazawa, Mikio Konishi, Ken Kato
-
Patent number: 5087433Abstract: In the production of SiC whisker for composite materials such as FRP, FRM, FRC and the like by vapor phase synthesis between silicon sulfide and carbon compound, SiC whisker suitable for the continuation and mass production is produced in industrial scale by using metallic Si as a starting material through a stage of contacting the metallic silicon with hydrogen sulfide gas to produce silicon sulfide gas, and a stage of contacting the silicon sulfide gas with carbon compound and, if necessary, a formed nucleus to deposit and grow whisker.Type: GrantFiled: December 5, 1990Date of Patent: February 11, 1992Assignee: Ibiden Co., Ltd.Inventors: Ryo Enomoto, Yoshimi Matsuno