Fusing Or Melting Inorganic Material Patents (Class 264/332)
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Patent number: 4999144Abstract: The present invention relates to a pressure self-combustion sintering method for obtaining a ceramic sintered body.Conventionally, in order to sinter ceramics by the pressure self-combustion sintering method, a mixture comprising metallic elements and non-metallic elements has been inserted into an airtight vessel and then a filament formed of W, Mo and the like as a heat source for starting a reaction has been placed within said airtight vessel followed by heating by adding energy to this heat source from outside of the airtight vessel and applying an isostatic pressure to the mixture comprising metallic elements and non-metallic elements to start a synthetic reaction of ceramics from one end of said mixture, thereby carrying out a chain synthetic sintering of ceramics by a reaction heat.Type: GrantFiled: October 27, 1988Date of Patent: March 12, 1991Assignees: Osaka University, Sumitomo Electric Industries, Ltd.Inventors: Yoshinari Miyamoto, Hirohiko Nakata
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Patent number: 4997605Abstract: A hot-pressed ceramic composite having good resistance to thermal shock and good erosion/corrosion resistance in molten alloys, and a method for producing said composite which comprises the blending of fused zirconia mullite with boron nitride.Type: GrantFiled: October 24, 1989Date of Patent: March 5, 1991Assignee: Union Carbide CorporationInventor: Gregory W. Shaffer
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Patent number: 4985163Abstract: A method for producing shaped heat-insulating bodies based on water-insoluble oxidic metal compounds particularly of the elements silicon and aluminum, clouding agents and other additives, whereby the bodies are thermally hardened and have a heat conductivity of 0.02 to 0.1 W/K.m at temperatures of approximately 300.degree. to 500.degree. C. and are comprised of (a) 100 parts by weight of water-insoluble oxidic metal compounds having a BET-surface of 10 to 700 m.sup.2 /g, with the provision that at least 5% by weight of these compounds have a BET-surface of at least 50m.sup.2 /g; (b) 0 to 100 parts by weight of mineral clouding agents having at least one absorption maximum in the wave length range of 1.5 to 10 .mu.m; and (c) 0.1 to 30 parts by weight of elements capable of forming a solid oxide having a standard formation enthalpy of less than minus 900 kJ/Mol. In addition, 0-100 parts by weight of mineral fibers can be added.Type: GrantFiled: June 4, 1986Date of Patent: January 15, 1991Assignee: Consortium fur Elektrochemische Industrie GmbHInventors: Gunter Kratel, Hans Katzer
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Patent number: 4983339Abstract: The invention relates to a process for shaping a material by isostatic compression at a temperature of at least 1300.degree. C. of a powder of said material in a tight sheath.The sheath is made from titanium or a titanium alloy and is internally coated with tantalum in such a way that the sheath can be embrittled during hot isostatic compression, by the diffusion of tantalum into the titanium or titanium alloy, in the presence of oxygen. In general, the titanium sheath is coated with tantalum by spraying in the presence of oxygen.The use of such a sheath makes it possible to avoid the operation of eliminating the sheath chemically or mechanically conventionally necessary in such processes.Type: GrantFiled: August 5, 1988Date of Patent: January 8, 1991Assignee: Commissariat a l'Energie AtomiqueInventors: Marcel Boncoeur, Thierry Lieven, Marc Palacio
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Patent number: 4978644Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron nitride material typically resulting in a body comprising a boron-containing compound, a nitrogen-containing compound and metal. The mass to be infiltrated may contain one or more inert fillers admixed with the boron nitride, to produce a composite by reactive infiltration, which composite comprises a matrix which embeds the filler material. The matrix, in a composite body containing filler material, comprises one or more of metal, a boron-containing compound and a nitrogen-containing compound. The relative amounts of reactants and process conditions may by altered or controlled to yield a body containing varying volume percents of ceramic, metal and/or porosity. The mass to be infiltrated can be contained within a refractory vessel having a venting means included therein.Type: GrantFiled: December 12, 1989Date of Patent: December 18, 1990Assignee: Lanxide Technology Company, LPInventors: Danny R. White, Terry D. Claar
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Patent number: 4960550Abstract: The encapsulation of ceramic preforms (10) for HIP processing is considerably simplified, and the use of standard laboratory glassware as encapsulation material is made possible, by placing non-sealed glass capsule parts (12, 14) around the preform (10) in the HIP pressure vessel (18), evacuating the vessel (18), heating the vessel (18) to a temperature at which the glass parts (12, 14) fuse together but do not collapse, and then pressurizing the vessel (18) and increasing the temperature therein as required for conventional HIP processing.Type: GrantFiled: July 20, 1989Date of Patent: October 2, 1990Assignee: Ford Aerospace CorporationInventor: Joseph M. Wright
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Patent number: 4952353Abstract: A process for densifying porous articles comprises providing a non-reactive container with a green article and sufficient solid encapsulating agent selected from the group consisting of tin and the tin-magnesium eutectic to encapsulate the green article when the agent is in the molten state. The temperature is raised sufficiently to melt the agent and to encapsulate the article. The encapsulated article is maintained at a pressure below the infiltrating pressure of the green article while heating the encapsulated article sufficiently to create a surface on the article that is essentially free of porosity and thereafter, the pressure on the encapsulated article is increased while maintaining the article at its sintering temperature for a sufficient time to increase the density of said article to at least about 98% of theoretical.Type: GrantFiled: December 28, 1989Date of Patent: August 28, 1990Assignee: GTE Laboratories IncorporatedInventor: Jeffrey T. Neil
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Patent number: 4946630Abstract: A method of making a silicon nitride comprising object by use of a low density reaction bonded body is disclosed. An uncompacted mixture of silicon powder and a fluxing agent is heated in a nitrogen atmosphere to react the mixture with the atmosphere to form a body consisting essentially of silicon nitride and having a dimension greater than and a density less than the finished product. The nitrided mixture is then hot pressed to produce a silicon nitride comprising object of desired dimension and density, which material is useful as a cutting tool material for machining metals.Type: GrantFiled: October 12, 1982Date of Patent: August 7, 1990Assignee: Ceradyne, Inc.Inventor: Andre Ezis
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Patent number: 4943398Abstract: A method for manufacturing a fused cast refractory article including the steps of pouring a molten refractory material into a cavity of a mold including a casting sand held by a negative pressure applied through the sand and against a thermoplastic film which surrounds the mold cavity, casting and cooling off the refractory material, wherein the negative pressure is maintained after the casting. The mold includes an upper mold portion including a frame, a casting sand, and a thermoplastic film; a bottom mold portion including a frame, a casting sand and a thermoplastic film; and a cavity defined by the thermoplastic film between the upper and bottom mold portion and having an inlet opening.Type: GrantFiled: November 12, 1987Date of Patent: July 24, 1990Assignee: Toshiba Monofrax Co., Ltd.Inventors: Shigeo Endo, Haruo Kawashima, Kimio Hirata, Yasuo Saito, Takao Uchiya, Hideo Yanagi
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Patent number: 4943320Abstract: A process for preparing ceramic-metal composites without melting the metal is disclosed. A compact or green body is made from a ceramic and a metal, and the compact is sealed in a vacuum in a container such as a glass envelope. The compact is then heated to a temperature below the melting point of the metal, but high enough so that the vapor pressure of the metal is significant, and the metal redistributes through the ceramic by evaporation and condensation. The composite thereby forms a body having ceramic particles uniformly coated by the metal. Products formed by the process and fabrication of a B.sub.4 C/Cr composite are also disclosed.Type: GrantFiled: December 15, 1988Date of Patent: July 24, 1990Assignee: The Regents of the University of CaliforniaInventors: Alexander Pechnik, M. Dean Matthews
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Patent number: 4925608Abstract: A method of joining two pre-sintered pieces of silicon carbide is disclosed. It entails polishing the surfaces to be joined to a mirror-finish, fitting the polished surfaces together to form a composite structure, and then subjecting the composite structure to hot isostatic pressing under conditions which are sufficient to form a joint which is essentially indistinguishable from the original silicon carbide pieces.Type: GrantFiled: September 27, 1988Date of Patent: May 15, 1990Assignee: Norton CompanyInventors: Guilio A. Rossi, Paul J. Pelletier
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Patent number: 4921655Abstract: In the preparation of compact, crystalline and pore-free moldings from an oxide ceramic, amorphous oxide powders of beryllium, magnesium, aluminum, boron, zirconium, thorium or silicon or mixed oxides of silicon with these elements, in which some of the oxygen is replaced by bound nitrogen, are used as starting materials. These amorphous oxide powders containing bound nitrogen are compressed in a first stage at above the glass transition temperature but below the crystallization temperature to give a glassy molding, and the latter is then heated in a second stage to above the crystallization temperature. In the case of the individual oxides, from 5 to 30% of the oxygen are replaced by bound nitrogen, and in the case of the mixed oxides of silicon with these elements from 50 to 90% of the oxygen are replaced by bound nitrogen.Type: GrantFiled: April 29, 1988Date of Patent: May 1, 1990Assignee: BASF AktiengesellschaftInventor: Hans-Josef Sterzel
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Patent number: 4917843Abstract: For joining shaped bodies of silicon nitride together, silicon nitride surfaces to be joined are first polished and then put into an apparatus for applying sputtered layers where they are first cleaned by ion bombardment in argon, followed immediately by sputtering with silicon in a nitrogen atmosphere such that a layer is deposited having a nitrogen content exceeding the Si.sub.3 N.sub.4 stoichiometric ratio. This readily provides a layer of the composition Si.sub.3 N.sub.5.5. A complementary nitrogen deficient layer is also provided in the joint before hot pressing, either in the form of a silicon layer that goes between the nitrogen-rich silicon nitride layers or in the form of a nitrogen-deficient silicon nitride layer sputtered onto a polished silicon nitride surface at relatively low nitrogen pressure. The parts are isostatically hot pressed together at 1500.degree. to 1750.degree. C. in a nitrogen atmosphere. The layers which are usually thinner than 1 .mu.Type: GrantFiled: October 30, 1987Date of Patent: April 17, 1990Assignee: Kernforschungsanlage Julich Gesellschaft mit beschrankter HaftungInventors: Erno Gyarmati, Xiliang Qiu
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Patent number: 4906426Abstract: A process for producing an improved quality alumina-silica-chromia fiber from a mixture of an alumina powder, a silica powder and a powder of a solid solution of chromia in alumina, providing a flowing melt, and forming fibers.Type: GrantFiled: February 8, 1989Date of Patent: March 6, 1990Inventor: Masafumi Yamamoto
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Patent number: 4879263Abstract: A sliding member formed of sintered silicon nitride shows improvement in strength and abrasion resistance when substantially all the .beta.-phase type fine silicon nitride particles present as a main component in the sintered silicon nitride have major diameters not exceeding 60 .mu.m and aspect ratios of not less than 5 and the aforementioned fine silicon nitride particles have a relative density of not less than 98%.Type: GrantFiled: September 17, 1985Date of Patent: November 7, 1989Assignee: Kabushiki Kaisha ToshibaInventors: Katsutoshi Komeya, Hashimoto, Masahiro, Katsutoshi Nishida, Michiyasu Komatsu
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Patent number: 4859531Abstract: A method for bonding a cubic boron nitride sintered compact to other cubic boron nitride sintered compact or to a body of shank material is disclosed. The method comprises forming a Ti layer of 0.01-1 .mu.m in thickness over a bonding interface between two cubic boron nitride sintered compacts or between a cubic boron nitride sintered compact and a body of shank material, forming a layer of Ni or Cu over the Ti layer to a thickness of 0.01-5 .mu.n, putting together the two cubic boron nitride sintered compacts or the cubic boron nitride sintered compact and the body of shank material with a 10-1,000 .mu.m foil of Al, Al-Ni alloy or Ag--Cu--In alloy being placed over the boding interface, and heating the cubic boron nitride sintered compact structure to temperatures above the meeting point of the metal foil and not exceeding 750.degree. C. in an inert atmosphere or in a vacuum.Type: GrantFiled: July 27, 1988Date of Patent: August 22, 1989Assignee: Sumitomo Electric Industries, Ltd.Inventors: Kazuwo Tsuji, Hitoshi Sumiya, Yoshiaki Kumazawa, Nobuo Urakawa, Keiichi Satoh
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Patent number: 4848984Abstract: A method of making a reaction bonded/hot pressed silicon nitride comprising object is disclosed. Second phase crystallites are formed prior to hot pressing. A mixture of silicon, SiO.sub.2, and 0.4-2.3 molar percent (by weight of the silicon) of oxygen carrying agents, i.e., Y.sub.2 O.sub.3 and Al.sub.2 O.sub.3, is performed and reaction nitrided to form discs or billets having at least 60% alpha Si.sub.3 N.sub.4 and a high proportion of second phase crystallites which displace substantially all silicate glass except for a controlled small quantity. The reactive amounts of Y.sub.2 O.sub.3, Al.sub.2 O.sub.3 and SiO.sub.2 are controlled to assure formation of substantially Y.sub.1 SiO.sub.2 N as the second phase crystallite. Al.sub.2 O.sub.3 is controlled in an amount of 0.4-4% by weight to ensure that the small proportion of glass serves to protect the oxynitrides against linear oxidation kinetics. The hot pressed material has no visual mottle porosity associated therewith.Type: GrantFiled: September 20, 1984Date of Patent: July 18, 1989Assignee: Ceradyne, Inc.Inventors: Andre Ezis, Elaine C. Beckwith
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Patent number: 4849142Abstract: The invention relates to producing relatively flaw free zirconia ceramic shapes requiring little or no matching by superplastic forging of a fully sintered or partially sintered preform. The preform is prepared by providing a starting powder comprising by weight from about 70% to about 100% zirconia and from about 0 to about 30% of stabilizing additives, e.g. commerically available TZ-3Y powder, cold pressing to obtain a preform of green density ranging from about 30% of theoretical density to about 75% of theoretical density and partially or fully sintering at atmospheric pressure, e.g. in argon or air at a temperature ranging from about 900.degree. C. to about 1900.degree. C. The superplastic forging is carried out by isothermally pressing the partially or fully sintered preform into substantially final shape utilizing a temperature and strain rate such that surface cracks do not occur, e.g. utilizing a temperature of 1310.degree. C.Type: GrantFiled: January 3, 1986Date of Patent: July 18, 1989Assignees: Jupiter Technologies, Inc., Cornell ResearchInventors: Prakash C. Panda, Edgar R. Seydel, Rishi Raj
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Patent number: 4847031Abstract: Self-resistance heated, electrically conductive, refractory evaporating boats containing titanium diboride can be reclaimed for reuse. If there is aluminum adhering to the boats, they are first leached in hot caustic solution to remove the aluminum. After rinsing and drying, the boats are ground to powder which is then screened. The screened powder is used to manufacture new boats.Type: GrantFiled: December 16, 1987Date of Patent: July 11, 1989Assignee: GTE Products CorporationInventors: Edward D. Parent, Edwin J. Spooner, Robert F. Scoledge, Jr.
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Patent number: 4843042Abstract: An aluminum nitride ceramic body with a thermal conductivity of at least 0.5 W/cm.K at 25.degree. C. is produced by shaping a particulate mixture of aluminum nitride powder and an additive selected from the group consisting of CaF.sub.2, SrF.sub.2, BaF.sub.2 and mixtures thereof into a compact and liquid phase sintering the compact.Type: GrantFiled: June 30, 1986Date of Patent: June 27, 1989Assignee: General Electric CompanyInventors: Stephen L. Dole, Ronald H. Arendt, Wayne D. Pasco
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Patent number: 4839119Abstract: Compact pore-free silicon carbide moldings are produced by compressing amorphous silicon carbide powder in the absence of sintering assistants at from 1400.degree. to 1800.degree. C. and under from 100 to 2000 kp/cm .sup.2 to give dense, glassy moldings. In a subsequent stage the resulting glassy moldings are converted into crystalline .alpha.-silicon carbide at from 1950.degree. to 2200.degree. C.Type: GrantFiled: February 26, 1988Date of Patent: June 13, 1989Assignee: BASF AktiengesellschaftInventor: Hans-Josef Sterzel
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Patent number: 4834917Abstract: Waste material such as toxic compounds, radioactive waste materials and spent nuclear fuel rods are encapsulated in a container system which is subjected to a hot pressure process to cause a protective powder material located around the waste material to form a dense matrix and function as a highly corrosion resistant and protective shroud. Embodiments include hot isostatic pressing and hot uniaxial pressing, the use of metal powder such as copper powder for the protective powder material or alternatively ceramic powder and, depending upon the embodiment chosen, the use of a single container or dual container system in which a first container is located within an outer container. Either or both of such containers may be cylindrical with a bellows-like side wall to facilitate compression thereof in an axial direction.Type: GrantFiled: June 23, 1987Date of Patent: May 30, 1989Assignees: Australian Nuclear Science & Technology Organization, The Australian National UniversityInventors: Eric J. Ramm, Albert E. Ringwood
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Patent number: 4832893Abstract: A method for producing PLZT generally expressed as (Pb.sub.1-x La.sub.x) (Zr.sub.1-y Ti.sub.y).sub.1-x/4 O.sub.3 (0<x.ltoreq.0.3, 0.ltoreq.y.ltoreq.1.0) comprises the steps of forming a coprecipitated body by reacting solution containing at least one of Pb, La and Ti with a zirconium-containing solution and a precipitation-forming solution, or (a) forming a solution containing at least one of Pb, La and Ti forming PLZT generally expressed as (Pb.sub.1-x La.sub.x) (Zr.sub.1-y Ti.sub.y).sub.1-x/4 O.sub.3 (0<x.ltoreq.0.3, 0.ltoreq.y.ltoreq.1.0) and a zirconium-containing solution and carrying out a hydrolysis reaction to produce a sol body, (b) drying and then presintering the coprecipitated body at a temperature of from 700.degree. to 1300.degree. C. to form a modified zirconia powder, (c) mixing the presintered body with a compound having a remaining component composition of a required PLZT composition, (d) presintering the mixture at a temperature of from 500.degree. to 1000.degree. C.Type: GrantFiled: December 16, 1987Date of Patent: May 23, 1989Assignees: Nippondenso Co., Ltd., Science and Technology Agency National InstituteInventors: Michio Hisanaga, Kazunori Suzuki, Masataka Naito, Shinichi Shirasaki
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Patent number: 4812280Abstract: A process for manufacturing large, fully dense, high purity TiB.sub.2 articles by pressing powders with a sintering aid at relatively low temperatures to reduce grain growth. The process requires stringent temperature and pressure applications in the hot-pressing step to ensure maximum removal of sintering aid and to avoid damage to the fabricated article or the die.Type: GrantFiled: April 17, 1986Date of Patent: March 14, 1989Assignee: The United States of America as represented by the Department of EnergyInventors: Arthur J. Moorhead, E. S. Bomar, Paul F. Becher
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Patent number: 4812272Abstract: A process for compacting a porous ceramic structural member having a compated shape and an optional size by encapsulation with material of the same type and capable of sintering and subsequently subjected to hot-isostatic pressing; immersing the preformed body in a suspension of a material of the same type in a solvent but which contains no sintering aid and forming a first encapsulating layer; evaporating the solvent; immersing the thus obtained body in a second suspension of a material in a solvent of the same type capable of sintering and which contains one or more sintering aids, and forming a second encapsulating layer; evaporating the solvent; subjecting the thus obtained body at an elevated temperature in an atmosphere of a protective gas for a sufficient period of time to sinter the same; isostatically compacting the body provided with a tight-sintered surface; and mechanically removing the encapsulating layers.Type: GrantFiled: February 5, 1987Date of Patent: March 14, 1989Assignee: Duetsche Forchungs- und Versuchsanstalt fur Luft- und Raumfahrt e.V.Inventors: Jurgen Heinrich, Manfred Bohmer
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Patent number: 4808337Abstract: A compressible bellows type metal canister is used in a hot pressing process for immobilizing high level radioactive nuclear waste material in the form of synthetic rock, the canister comprises a base wall and a corrugated bellows side wall of generally circular cross-section, concentrically arranged within the corrugated side wall is a cylindrical liner. In the center of the base wall a conically-tapered aperture is provided with a filter plug. Diametrically opposed apertures are provided in the base wall and are connected by an outlet pipe for removal of waste gases.Type: GrantFiled: July 14, 1986Date of Patent: February 28, 1989Inventors: Eric J. Ramm, Wilhelmus J. Bukyx, John G. Padgett, Alfred E. Ringwood
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Patent number: 4806279Abstract: A vibratory processing arrangement including an apparatus comprising three main stages. Namely, a high level waste vibrating impregnator, a vibrating calciner and a vibratory powder mixer.The waste impregnator comprises a downwardly inclined trough having flexible mountings and a vibrator at its upstream end, a hood structure and a series of liquid sprays connected to a high level waste supply tube.The vibratory calciner comprises a downwardly inclined tube connected to a downstream discharge tube. The discharge tube has an inlet pipe for entry of reducing gas. The reducing gas passes upwardly through the tubes to a gas discharge take-off tube near the upstream end of the downwardly inclined tube. A vibrator is tuned to provide the desired flow rate through the downwardly inclined tube.Calcined discharged powder falls downwardly into the vibratory mixer, which has a vibratory actuator and flexible mountings.Type: GrantFiled: December 1, 1986Date of Patent: February 21, 1989Assignees: Australian Atomic Energy Commission, Australian National UniversityInventor: Eric J. Ramm
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Patent number: 4792468Abstract: A process of forming a refractory mass on a surface, which process includes spraying against that surface a mixture of refractory particles and oxidisable particles which react exothermically with oxygen to generate sufficient heat to soften or melt at least the surfaces of the refractory particles and so bring about formation of said refractory mass, and causing the sprayed mixture to be heated sufficiently to cause the oxidisable particles to undergo such exothermic reaction, the granulometry of the particles which are sprayed in the mixture being such that the mean of the 80% and 20% grain sizes of the refractory particles is greater than the mean of the 80% and 20% grain sizes of the oxidisable particles and that the size range spread factor of the refractory particles is at least 1.2.Type: GrantFiled: December 2, 1985Date of Patent: December 20, 1988Assignee: GlaverbelInventors: Pierre Robyn, L/e/ on-Philippe Mottet, Pierre Deschepper
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Patent number: 4786448Abstract: There are disclosed a plastic processing method of the pressure of pressureless sintered ceramic body composed of at least one aluminum-containing compound selected from the group consisting of aluminum oxide, aluminum nitride and aluminum oxynitride and at least one hard compound selected from the group consisting of carbides, nitrides and oxides of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and silicon and mutual solid solutions thereof, the content of said at least one aluminum-containing compound is 5 to 95% by volume, comprising subjecting the ceramic body to plastic deformation at a temperature of 1300.degree. C. or higher, under a stress of 15 kg/mm.sup.2 or smaller and at a strain rate of 10.sup.-3 /sec or less in a reducing atmosphere or in vacuum, and a ceramics-made molded material comprising a composite ceramic body composed of the same as mentioned above.Type: GrantFiled: August 27, 1986Date of Patent: November 22, 1988Assignee: Toshiba Tunglogy Co., Ltd.Inventors: Mikio Fukuhara, Yuji Katsumura, Akira Fukawa, Mutsuo Asakawa, Tomio Urushihata, Isao Miyakawa, Kazuhiro Sawada
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Patent number: 4786304Abstract: A method of molding a hollow, fiber reinforced glass matrix composite article. Reinforcing fibers are placed in a mold cavity. A billet of high temperature stable glass matrix material is heated above its flow point. The thus heated matrix materials is flowed into the mold cavity from a point inside of the article being formed and at the relative midpoint along its vertical axis. Improved article tolerance control and minimized article preform fiber disturbance is achieved.Type: GrantFiled: August 10, 1987Date of Patent: November 22, 1988Assignee: United Technologies CorporationInventor: Otis Y. Chen
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Patent number: 4784818Abstract: A shaped article of superplastic ceramic composed of zirconia toughened ceramic containing, or not containing, fine alumina powder is produced by deforming the ceramic under the action of stress at a temperature in the range of superplastic temperatures thereof.Type: GrantFiled: March 28, 1986Date of Patent: November 15, 1988Assignees: Agency of Industrial Science & Technology, Ministry of International Trade & IndustryInventors: Fumihiro Wakai, Shuzo Kanzaki, Shuji Sakaguchi
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Patent number: 4778626Abstract: A dry, pourable particulate mixture of nuclear waste and synthetic rock-forming components is produced by supplying the rock forming components in dry particulate form to a mixer, supplying the nuclear waste in liquid phase and operating the mixer to distribute the waste substantially uniformly through the synthetic rock components; the mixture is calcined to produce a precursor powder which is adapted to be used in a hot pressing process to form synthetic rock throughout which the radioactive nuclear waste is distributed and immobilized. A reducing gas atmosphere is preferably maintained in the calcining process stage, the gas being for example pure hydrogen or a mixture of hydrogen in nitrogen in proportions which are non-explosive. A screw type or paddle type conveyor can be used for the mixing and calcining stages although the calcining can be effected in a vertically downwardly directed tube device having associated heating means such as microwave heating.Type: GrantFiled: October 27, 1986Date of Patent: October 18, 1988Assignees: Australian Nat'l Univ. of Acton, Australia Nuclear Science & Technology OrganisationInventors: Eric J. Ramm, Wilhelmus J. Buykx, Alfred E. Ringwood
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Patent number: 4762656Abstract: The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.Type: GrantFiled: October 10, 1986Date of Patent: August 9, 1988Assignee: The United States of America as represented by the United States Department of EnergyInventors: Ambrose H. Ballard, Thomas G. Godfrey, Jr., Erb H. Mowery
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Patent number: 4759887Abstract: A process for the manufacture of shaped bodies from silicon granulates for producing silicon melts includes first incipiently melting silicon grains on their surfaces, so that they bond with their neighbors in the process and, after solidifying, form a porous compound shaped body which only then may be melted completely. Such compound shaped bodies can be manufactured continuously or semi-continuously and converted without difficulty by a subsequent step into the molten state. An apparatus for producing shaped bodies is also provided which preferably employs an electron beam, to supply energy to incipiently melt the granulate.Type: GrantFiled: May 12, 1986Date of Patent: July 26, 1988Assignee: Heliotronic Forschungs- und Entwicklungs-gesellschaft fur Solarzellen-Grundstoffe mbHInventors: Joachim Geissler, Deiter Helmreich, Roland Luptovits, Maximilian Semmler, Burkhard Walter
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Patent number: 4752427Abstract: A method for plastic working of ceramics comprising the steps of causing a sintered or pre-sintered body of polycrystalline ceramics containing at 20.degree. C. tetragonal-phase zirconia crystals to undergo plastic deformation at a temperature of about 1,000.degree. C. to about 1,600.degree. C. and then heating the ceramics body at a temperature of about 1,300.degree. C. to about 1,650.degree. C.Type: GrantFiled: July 11, 1986Date of Patent: June 21, 1988Assignees: Agency of Industrial Science and Technology, Nippon Kagaku Togyo Co., Ltd.Inventors: Fumihiro Wakai, Shuji Sakaguchi, Hiroshi Ohnishi, Hiroshi Tomatsu
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Patent number: 4749539Abstract: A process is disclosed for producing corrosion resistant silicon nitride bodies from compositions of pure silicon nitride, lanthanum oxide with and without aluminum oxide by hot pressing.Type: GrantFiled: May 29, 1984Date of Patent: June 7, 1988Assignee: GTE Products CorporationInventor: Martin Y. Hsieh
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Patent number: 4744943Abstract: A process for preparing dense, consolidated bodies, the process comprising compressing in a forging press an isostatic die assembly, the assembly comprising a preform surrounded by a fluid pressure-transmitting medium, the medium and the preform being contained in a shell having an open top; under sufficient conditions of temperature, time and pressure that a dense, consolidated body of desired shape is formed, and then recovering the body by separating the body from the fluid pressure-transmitting medium.Type: GrantFiled: December 8, 1986Date of Patent: May 17, 1988Assignee: The Dow Chemical CompanyInventor: Edward E. Timm
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Patent number: 4734234Abstract: Pore-free, compact moldings of silicon nitride are produced by a method in which amorphous silicon nitride powder is compressed in a first stage at from 1200.degree. to 1350.degree. C. and from 50 to 600 kp/cm.sup.2 to give a glassy molding, and the silicon nitride is converted in a second stage to crystalline silicon nitride at from 1400.degree. to 1800.degree. C. without the use of pressure.Type: GrantFiled: January 21, 1986Date of Patent: March 29, 1988Assignee: BASF AktiengesellschaftInventor: Hans-Josef Sterzel
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Patent number: 4732719Abstract: The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forgingThis invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.Type: GrantFiled: January 3, 1986Date of Patent: March 22, 1988Assignee: Jupiter Technologies, Inc.Inventors: Prakash C. Panda, Edgar R. Seydel, Rishi Raj
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Patent number: 4715892Abstract: The present invention is directed to a cermet material comprising a matrix of metal or alloy with ceramic particles distributed therein. The cermet includes a glass binder for bonding between the metal or alloy and the ceramic particles.Type: GrantFiled: October 30, 1986Date of Patent: December 29, 1987Assignee: Olin CorporationInventor: Deepak Mahulikar
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Patent number: 4705659Abstract: A process is disclosed for fabricating a free-standing thin or thick film structure. One embodiment of the process includes the steps of providing a substrate of a first refractory material, forming a layer of carbon on the substrate, and depositing a film of a second refractory material on top of the layer of carbon. This sandwich structure is heated in an oxidizing ambient to cause the oxidation of the carbon layer leaving the second refractory material as a free-standing film.Type: GrantFiled: July 7, 1986Date of Patent: November 10, 1987Assignee: Motorola, Inc.Inventors: Jonathan J. Bernstein, T. Bruce Koger, Charles S. Chanley
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Patent number: 4692288Abstract: A method including embedding a porous silicon ceramic compact, or workpiece, in a powder which is not sinterable at the process temperature, and subjecting the powder and embedded compact to heat and pressure in a hot isostatic press. The powder transmits the pressure to the compact. The powder may be the same material as the compact, except without a sintering agent, or the powder may be graphite powder. The grain size of the powder is between 2 .mu.m and 50 .mu.m. The powder and embedded compact are placed in a container prior to hot pressing; the container may be made of thin sheet metal or of quartz glass.Type: GrantFiled: October 21, 1980Date of Patent: September 8, 1987Assignee: MTU Motoren-und Turbinen-Union Munchen GmbHInventors: Axel Rossmann, Werner Huther
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Patent number: 4690797Abstract: A method for the manufacture of large area silicon crystal bodies suitable for use in the manufacture of solar cells wherein silicon powder having a small grain size is used as the starting material. This powder is compressed to form a thin layer in a suitable form, the form having at least a surface composed of silicon or a silicon compound. The form is filled to a depth approximating the final dimensions of the article. The powder is sintered in the form, and the compressed, sintered layer is converted into a self-supporting silicon foil. This foil is melted partially up to at least half its thickness and recrystallized in a two-stage temperature treatment. The melting occurs by means of a single-sided energy irradiation. The silicon foil is not deteriorated in terms of its mechanical stability and shaped by means of the single-sided, optical type heating.Type: GrantFiled: September 17, 1986Date of Patent: September 1, 1987Assignee: Siemens AktiengesellschaftInventors: Achim Eyer, Armin Raeuber, Norbert Schillinger
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Patent number: 4689188Abstract: Alternate layers of mats of specially coated SiC fibers and silicon monotapes are hot pressed in two stages: In the first a die is heated to about 600.degree. C. in a vacuum furnace and maintained at this temperature for about one-half hour to remove fugitive binder.In the second stage the die temperature is raised to about 1000.degree. C. and the layers are pressed at between 35 MPa and 138 MPa. The resulting preform is placed in a rector tube where a nitriding gas is flowed past the preform at 1100.degree. C. to 1400.degree. C. to nitride the same.Type: GrantFiled: July 16, 1986Date of Patent: August 25, 1987Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventor: Ramakrishna T. Bhatt
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Patent number: 4689196Abstract: An electrical contact comprises 5 to 20 weight percent tungsten carbide, 0.5 to 3 weight percent graphite, balance silver. The contact has low erosion rate, low contact resistance, and anti-welding properties.Type: GrantFiled: February 26, 1987Date of Patent: August 25, 1987Assignee: GTE Products CorporationInventor: Chi H. Leung
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Patent number: 4683118Abstract: A process and apparatus for producing a pressed powder body from at least two different kinds of ultrafine particles. Ultrafine particles of at least two different materials are uniformly mixed together and the mixture is sprayed onto an objective surface whereby the spray pressure causes the particles to adhere and form the pressed powder body. The apparatus includes mixing means, means for conveying the mixture of ultrafine particles, and a pressed powder body forming chamber including nozzle means for spraying the mixture of ultrafine particles, an objective surface and means for evacuating the chamber and introducing an inert gas therein.Type: GrantFiled: October 9, 1985Date of Patent: July 28, 1987Assignee: Research Development Corporation of JapanInventors: Chikara Hayashi, Seiichiro Kashu
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Patent number: 4678761Abstract: Magnesium oxide ceramic bodies may be strengthened by inclusion of zirconium oxide particles, and may be further sintered to a density approaching theoretical density by conventional sintering techniques by inclusion of sintering aids, such as manganese oxide and iron oxide.Type: GrantFiled: October 29, 1985Date of Patent: July 7, 1987Assignee: The Dow Chemical CompanyInventors: Anil Virkar, Thomas C. Yuan
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Patent number: 4671917Abstract: Molten oxide of grinding material, refractory material, etc., being poured into a circular casting space formed between coaxially arranged inner and outer cylinders and cooled by the water contained in the inner cylinder. Thus, the molten oxide is cooled radially from the center of the inner cylinder and solidified. The outer cylinder includes two segments which separate from each other for facilitating putting the molten oxide into the casting space and taking the resulting solidified product out of the casting space.Type: GrantFiled: July 30, 1985Date of Patent: June 9, 1987Assignee: Japan Abrasive Co., Ltd.Inventors: Akira Iwata, Masahiro Tamamaki, Genji Tanaka, Masaaki Taniguchi, Kouji Tsuda
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Patent number: 4666645Abstract: The present invention discloses a process of forming glass, glass-ceramic or ceramic matrix, fiber reinforced composite articles. The method comprises preparing both the matrix and the reinforcement into fibers, which are then chopped into relatively short lengths. These chopped fibers are then formed into hybrid felt papers comprising a mixture of both reinforcing fibers and matrix fibers. These felt papers are then cut into preforms and stacked one on top of the other to form a lay-up. The lay-up is then placed in a die and densified to form the composite article.Type: GrantFiled: April 20, 1984Date of Patent: May 19, 1987Assignee: United Technologies CorporationInventors: Karl M. Prewo, George K. Layden
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Patent number: 4664731Abstract: A method of making fiber reinforced glass composite articles utilizes preregnated preforms which are bound with a temporary plastic binder. The binder is removed in a gradient oven and the frit or preform is drawn through a pultrusion die assembly heated to the degree necessary to render the frit workable. Deformation in the heated die assembly is maintained during cooling, resulting in a formed glass composite article.Type: GrantFiled: January 7, 1985Date of Patent: May 12, 1987Assignee: The United States of America as represented by the Secretary of the NavyInventors: George K. Layden, Karl M. Prewo