Abstract: A highly heat-conductive aluminum nitride sintered body comprising 95.5 to 99.8% by weight of an aluminum nitride grain phase having an average grain size of 2 to 10 .mu.m and the rest being substantially a dysprosium oxide phase and having a density of at least 99% of the theoretical density, at least 30% by weight of the oxide phase existing at the triple points of the aluminum nitride grains. By forming an alumina-based oxide layer on the sintered body and further forming on the oxide layer a plating layer of Ni and/or Cu via a vapor deposition layer, there can be obtained a semiconductor substrate having a high bonding strength to solder.

Abstract: Shaped articles of polycrystalline AlN and AlN-containing composites; the AlN articles having thermal conductivities of at least about 70 W/mK (watts/meter .degree.K); the AlN component effecting good thermal conductivity in the composited articles.

Abstract: An aluminum nitride powder obtained by firing and reacting a mixture of alumina and carbon in a nitrogen-containing atmosphere is disclosed, the aluminum nitride powder having an oxygen content of not more than 2.0% by weight, an iron content of not more than 20 ppm, a silicon content of not more than 100 ppm, and a titanium content of not more than 20 ppm and having has a tapped density of at least 1.0 g/cm.sup.3. An aluminum nitride powder containing from 0.01% to 10% by weight of a sintering aid is also disclosed, the aluminum nitride powder having an oleophilic surface and having a tapped density of at least 1.0 g/cm.sup.3. The aluminum nitride powder of the present invention has excellent moldability, has a high tapped density, is less in formation of coagulated particles, and has a sharp particle size distribution.

Abstract: A method for the production of a nitride of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium, gallium, indium or thallium either alone or as mixtures is claimed. Ammonia and a halide of at least one of these elements are heated by means of a direct electric current plasma in a non-oxidizing gas in a reactor in which recirculation is induced such that the defined recirculation ratio is greater than 2.5 and preferably greater than 4.0. Any titanium halide present shall be less then 40% by weight of mixed halides.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies and to the novel products made thereby. In its more specific aspects, this invention relates to a method of producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reacting, in one embodiment, a powdered parent metal, in molten form, with a bed or mass comprising a boron carbide material and, optionally, one or more inert fillers, to form the body. In another embodiment, both of a powdered parent metal and a body or pool of molten parent metal are induced to react with a bed or mass comprising a boron carbide material, and, optionally, one or more inert fillers.

Abstract: The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 --ZrC--Z composite body, by utilizing a post-treatment technique. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.

Abstract: Shaped refractory products, particularly in the form of hollow spheres, and a process for their formation. The process involves dispersing particles of silica or a metal oxide, e.g. Al.sub.2 O.sub.3, in an organic polymer, shaping the dispersion into a desired shape, heating the shaped dispersion in a non-oxidizing atmosphere to carbonize the polymer, and heating the carbonized product at high temperature in a non-oxidizing atmosphere containing nitrogen so that some of the oxide is converted to the corresponding nitride and the particles of unreacted oxide sinter together. The ratio of oxide to carbon should be high so that some but not all of the oxide is converted to the nitride and, preferably, only a relatively small amount should be converted. The resulting refractory material is strong and can be used for a variety of uses, e.g. catalyst supports, packing materials and insulating materials.

Abstract: Disclosed is a process for producing an ultrafine powder of aluminum nitride. This process is characterized in adding 1-5 wt % of aluminum nitride powder to the mixture of alumina and carbon black and heating the resulting powder mixture at a temperature of 1550.degree.-1650.degree. C. in an atmosphere of nitrogen. Preferably, prior to heating, the powder mixture is shaped into a compact. The aluminum nitride powder prepared by the process of the present invention has an average particle diameter of about 0.45 micron and a purity of above 98.1%, and is therefore a very suitable material for making printed circuit boards and heat release boards for IC, LSI and VLSI.

Abstract: A process for producing aluminum nitride powders is disclosed, which comprises mixing a water-soluble aluminum-containing compound or an aluminum alkoxide and a water-soluble carbon-containing compound and/or a water-soluble nitrogen-containing compound, with water; drying the mixture to obtain a solid; and calcining the solid in a nitrogen-containing non-oxidative atmosphere. According to the process of the invention, high-purity uniform aluminum nitride fine powders can be obtained rapidly and inexpensively.

Abstract: The invention relates to ceramic composite articles formed by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix a metal-oxidant reaction product. The bed or preform includes a dross material.

Abstract: By supplying gaseous nitrogen throughout a discrete aliquot of a preferably pelletized mixture of aluminum oxide, carbon and, optionally, calcium oxide during the carbothermal reduction thereof to aluminum nitride and continuously removing gaseous reaction products therefrom, a high quality aluminum nitride is produced. One means of supplying gaseous nitrogen to the mixture of solid reactants is a perforated tray having a hollowed-out bottom. Gaseous nitrogen supplied to the hollowed-out portion flows through the perforations and throughout solid reactants contained in the tray. The carbon may be alternatively supplied, in whole or in part, as a gaseous reactant.

Abstract: A method for preparing high-purity aluminum nitride having high thermal conductivity and heat resistance for aluminum nitride substrates, which comprises the steps of reacting an organic aluminum compound with an aminotriazine in a solvent to obtain an aluminum nitride precursor, separating the precursor form the solvent, and heating the precursor at a temperature of 600.degree. C. or more in a reducing atmosphere and/or a non-oxidizing atmosphere. An aluminum nitride sinter is prepared by, if necessary, adding a sintering auxiliary to the above aluminum nitride powder, molding the powder into a desired shape, and then sintering the molded material at a temperature of 1,600.degree. to 2,000.degree. C. in a non-oxidizing atmosphere.

Abstract: Metal nitride powder is prepared by heating a mixture substantially containing powder of a metal oxide or a metal hydroxide in a mixed gas of ammonia gas (NH.sub.3) and a hydrocarbon gas (CmHn) at a temperature ranging from 1300.degree. C. to 1,600.degree. C., in which the mixed gas has a ratio of ammonia gas (NH.sub.3) to hydrocarbon gas (CmHn) translated into CH.sub.4, ranging from 10 (NH.sub.3) to 1.0 (CH.sub.4) to 2,000 (NH.sub.3) to 1 (CH.sub.4), by volume.The metal nitride powder contains lesser amounts of oxygen and carbon.

Abstract: Nitride powders of high surface area, uniform small particle size and high purity are prepared by forming in an aqueous medium a homogeneous combination of a soluble or colloidally dispersible compound of a multivalent metal with a water soluble oxygen oxygenated carbonaceous polymer, e.g., by mixing an aluminum or other metal salt with polyacrylic acid or mixing colloidal hydrated alumina, or other such metal oxide, with a water soluble oxygenated carbonaceous polymer such as sucrose or methyl cellulose. The resulting precipitate or gel is dried and calcined in a nitriding atmosphere, forming a nitride powder which is highly suitable for fabrication of ceramic bodies by sintering at lower than conventional temperatures.

Abstract: An aluminum nitride powder has a crystallite size of 40 to 150 nm, measured by powder diffractometry and evaluated by the method of Scherrer, a primary particle size of 0.1 to 0.5 .mu.m, a specific surface according to BET of 5 to 50 m.sup.2 /g and a degree of whiteness of more than 91%, measured using light of a 400 to 700 nm wavelength against barium sulfate analytical reagent as standard of whitness.To prepare this aluminum nitride powder, metallic aluminum and monoamminealuminum chloride [AlCl.sub.3 (NH.sub.3)] are first molten together in an inert gas atmosphere at temperatures above 125.degree. C. and allowed to react with one another with evolution of hydrogen. 8 to 20 g of ammonia are then introduced per hour per mol of monoamminealuminum chloride into the aluminum-containing monoamminealuminum chloride melt at temperatures between 250.degree. and 400.degree. C., aluminum nitride being precipitated as a solid until the conversion of the aluminum is complete.

Abstract: Disclosed herein is an aluminum nitride powder having the improved water-resistance, which is obtained by treating the aluminum nitride powder with an inorganic or organic phosphoric acid compound followed by heating at about 150.degree. to 800.degree. C. when the organic phosphoric acid compound is used.

Abstract: A process for producing aluminum nitride powder by reacting nitrogen gas with a mixture of alumina and carbon is disclosed, in which a solid organic compound is added to the mixture.

Abstract: Methods are described for preparing aluminum nitride of controllable morphology for ceramic and heat conduction applications. The methods comprise forming spherical particles or flakes of an intermediate, RA1NH, followed by heating the spheres or flakes of RA1NH at elevated temperatures to produce high purity aluminum nitride of corresponding morphology. Spheres of RA1NH are formed by (i) freezing a suspension of RA1NH in a liquid medium and thawing, by (ii) aging the suspension, or by (iii) dissolving RA1NH in a liquid medium and precipitating it. Flakes are formed by freezing a suspension of RAINH in a liquid medium and removing frozen medium from the frozen suspension.

Abstract: The invention relates to method for producing composite ceramic articles by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix a metal-oxidant reaction product, and the bed or preform includes a dross material.

Abstract: A process is given for the production of transparent aluminum nitride films in which the aluminum nitride films comprise a nomocrystal and are obtained by evaporation of ammine salts of aluminum iodide in an evaporation zone and subsequent ammonolysis in a decomposition zone at 380.degree. to 550.degree. C.

Abstract: A process is given for the production of transparent aluminum nitride coatings in which the aluminum nitride coatings are obtained by evaporation of ammine salts of aluminum iodide in an evaporation zone and subsequent ammonolysis in a decomposition zone at temperatures between 550.degree. and 1200.degree. C.

Abstract: A one step combustion process for the synthesis of dense aluminum nitride compositions is disclosed. The process comprises igniting pure aluminum powder in a nitrogen atmosphere at a pressure of about 1000 atmospheres or higher. The process enables the production of aluminum nitride bodies to be formed directly in a mold of any desired shape.

Abstract: A method for producing materials having a high purity, which comprises forming an oxidation reaction product of a parent metal and an oxygen-containing vapor-phase oxidant, comminuting the resulting ceramic body and leaching any non-oxidation reaction product and/or corresponding filler materials therefrom, and recovering said substantially pure materials.

Abstract: A method of making fine particulate aluminum nitride, including the steps of reacting gaseous aluminum trichloride with aluminum-containing metallic material at elevated temperature to convert some of the trichloride to monochloride gas; introducing a gaseous nitrogen source to the monochloride-containing gas for reacting nitrogen with the monochloride to form fine particulate aluminum nitride; conducting a flow of gas comprising aluminum trichloride having the particulate nitride entrained therein to a cooling locality; there condensing the trichoride and accumulating the condensed trichloride and particulate nitride; and periodically reevaporating and removing the trichloride from the cooling locality for separating out and recovering the accumulated nitride.

Abstract: A method for preparing high-purity aluminum nitride having high thermal conductivity and heat resistance for aluminum nitride substrates, which comprises the steps of reacting an organic aluminum compound with an aminotriazine in a solvent to obtain an aluminum nitride precursor, separating the precursor from the solvent, and heating the precursor at a temperature of 600.degree. C. or more in a reducing atmosphere and/or a non-oxidizing atmosphere. An aluminum nitride sinter is prepared by, if necessary, adding a sintering auxiliary to the above aluminum nitride powder, molding the powder into a desired shape, and then sintering the molded material at a temperature of 1,600.degree. to 2,000.degree. C. in a non-oxidizing atmosphere.

Abstract: A method of forming a carbothermally reduced powder of nitrides or carbides is disclosed. The product powder consists principally of unagglomerated particles and is formed by providing a collection of precursor particles in colloidal dispersion, adding to the dispersion a polymerizable monomer, polymerizing the monomer to matrix the precursor particles in discrete, well dispersed positions and carbothermally reducing the particles followed by removing excess carbon by burning. The polymer matrix acts an an agglomerate-inhibiting carbon source during carbothermal reduction.

Abstract: Admixing an aluminum alkyl, and optionally a boron compound, with a hydride of nitrogen in the gas phase and maintaining a gas phase temperature, optionally in the presence of a carrier gas, and producing aluminum nitride alone or in admixture with a precursor thereof or boron nitride or both.

Abstract: A method to produce an article of commerce comprising a self-supporting ceramic body by oxidation of a molten parent metal with a vapor-phase oxidant, includes applying to a surface of the parent metal a layer at least one dopant material therein. The layer is thin relative to the thickness of the ceramic body. Upon heating the parent metal to a molten state in the presence of the oxidant, e.g., air, an oxidation reaction product is formed on the molten metal which, because of the effect of the dopant material, migrates through the growing oxidation reaction product so as to be exposed to the oxidant to form additional oxidation reaction product to and beyond the depth of the applied dopant material layer. Suitable temperature and oxidizing conditions are maintained for a time sufficient to produce a self-supporting ceramic body.

Abstract: A process for producing an aluminum nitride powder by reacting a mixture of alumina and carbon with a nitrogen gas, wherein the mixture of alumina and carbon being contacted with a nitrogen-containing inert gas at a temperature of 1,000.degree. to 1,400.degree. C. at a pressure of not higher than 0.1 atmosphere before a reaction is started to form aluminum nitride.

Abstract: A method of making self-supporting ceramic composite structures having filler embedded therein includes infiltrating a permeable mass of filler with polycrystalline material comprising an oxidation reaction product obtained by oxidation of a parent metal such as aluminum and optionally containing therein non-oxidized constituents of the parent metal. The structure is formed by placing a parent metal adjacent to a permeable filler and heating the assembly to melt the parent metal and provide a molten body of parent metal which is contacted with a suitable vapor-phase oxidant. Within a certain temperature region and optionally aided by one or more dopants in or on the parent metal, molten parent metal will migrate through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow so as to embed the adjacent filler and provide the composite structure.

Abstract: A method of making metal carbide, nitride, or boride powders and mixtures thereof by direct reduction of metal compounds comprises (a) forming a reactant mixture, (b) heating the reactant mixture to temperatures that cause solid reactants to vaporize and above which the metal precursor compounds are reduced, (c) passing the heated reactant mixture through a converging-diverging nozzle designed to reduce the temperature of the mixture to a temperature and for a time sufficient for further product species to form and for nuclei to form and grow by condensation to form the product powders, and (d) exhausting the mixture and product powders from the nozzle into an expansion chamber.

Abstract: Metal carbide and metal nitride powders produced by the carbothermal reduction of one or more metal oxides reacted with a binder material and a carbonaceous additive or optionally, a binder capable of supplying carbon to the reaction. The metal oxides are selected from among SiO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2, HfO.sub.2 and B.sub.2 O.sub.3 and are combined with the binder in the presence of carbon to form granules having a controlled pore volume. The granules are then subjected to a carbothermal reduction reaction, in the presence of a nitrogen or a neutral atmosphere, to produce metal nitrides or metal carbides respectively, having an excess of carbon incorporated therein. The product is subsequently heated to react the excess carbon within the compound with oxygen from the atmosphere to form carbon monoxide gas, which may be removed by an optional exhaust system.

Abstract: The invention concerns self-supporting ceramic structures, including ceramic composite structures embedding a filler, and methods of making them. The ceramic structures comprise a polycrystalline material made by oxidation of a body of molten parent metal with an oxidant. The polycrystalline material has a first region substrate surmounted by a terminal region stratum which is integral with the first region. The terminal region stratum is harder and of denser, finer crystalline structure than the first region substrate and is formed in a reaction stage subsequent to the reaction stage in which the first region of polycrystalline material is formed. Growth of the first stage is attained by attenuating or interrupting the transport of molten parent metal to the first region under conditions which nonetheless leave or maintain therein enough oxidizable molten parent metal to form the polycrystalline material of the terminal region.

Abstract: A method for producing an alumina of high purity, which comprises forming an oxidation reaction product of an aluminum parent metal and an oxygen-containing vapor-phase oxidant, comminuting the resulting ceramic body, and leaching any non-alumina materials therefrom, and recovering said substantially pure alumina material.

Abstract: A process for producing non-oxide compounds such as silicon nitride and silicon carbide by using a multi-stage apparatus constructed of a raw material drier section, a reactor section including a multiplicity of reaction vessels, and a non-oxidizing gas feeder section, is disclosed. The sections are arranged serially in the vertical direction. Raw materials are reacted with one another while fluidizing or bubbling by a hot non-oxidizing gas (argon or nitrogen) occurs in the raw material drier section and reaction vessels.

Abstract: Process for producing high purity aluminum nitride powder by reacting aluminum sulfide with gaseous ammonia at an intermediate temperature (about 700.degree. C.) and holding at that temperature until an intermediate product (Al.sub.x N.sub.y S.sub.z) is formed where x, y, and z are integers; then further heating to a temperature above 1100.degree. C. and reacting with gaseous ammonia. A high purity, low oxygen containing, free flowing powder is produced. A posttreatment using a carbon source such as graphite further reduces the oxygen content. The oxygen content can be further reduced by reacting the aluminum nitride formed with carbon at about 1600.degree. C.

Abstract: A process for making fine, uniform metal nitride powders that can be hot pressed or sintered. A metal salt is placed in a solvent with Melamine and warmed until a metal-Melamine compound forms. The solution is cooled and the metal-Melamine precipitate is calcined at a temperature below 700.degree. C. to form the metal nitrides and to avoid formation of the metal oxide.

Abstract: A method of synthesizing amorphous Group IIIA-Group VA compounds. A first solution is prepared which consists of a tris(trialkylsilyl) derivative of either a Group IIIA or Group VA element dissolved in an organic solvent. A second solution is then prepared which consists of a halide of the other of the Group IIIA or Group VA element dissolved in an organic solvent. Then the first and second solutions are mixed such that a Group IIIA-Group VA compound is formed along with a trialkylhalosilane by-product. The final step of the method consists of removing the trialkylhalosilane by-product and organic solvent mixture to form the Group IIIA-Group VA condensed phase.

Abstract: The present invention relates to a novel crystalline massive aluminosilicate with an expanded structure and to its process of manufacture. The particular structure is a closed cell structure containing nitrogen. It is obtained by: grinding industrial glass; adding aluminum based nitride in the proportion of 0.1 to 20% by weight with respect to the weight of the ground industrial glass; mixing the ground glass and so-added nitride; oxidizing the nitride within said mixture by heating to a temperature of 800.degree. to 1000.degree. C. for about 1 hour, and cooling and recovering the expanded crystalline aluminosilicate. The material has multiple applications in the building industry and in the construction of furnaces, in the manufacture of fireproof walls and doors, and in naval construction, with various advantages over prior art materials.

Abstract: A fluid bed reactor for treatment of refractory materials with a hot fluidizing gas and a method to use same. Both the refractory materials and the fluidizing gas are introduced from the top of the reactor. Unusually high reaction temperatures of up to 2000.degree. C. are maintained in the reaction chamber due to the presence of heating elements within the reactor and due to countercurrent heat transfer.

Abstract: Metal carbide and metal nitride powders produced by the carbothermal reduction of one or more metal oxides reacted with a binder material and a carbonaceous additive or optionally, a binder capable of supplying carbon to the reaction. The metal oxides are selected from among SiO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2, HfO.sub.2 and B.sub.2 O.sub.3 and are combined with the binder in the presence of carbon to form granules having a controlled pore volume. The granules are then subjected to a carbothermal reduction reaction, in the presence of a nitrogen or a neutral atmosphere, to produce metal nitrides or metal carbides respectively, having an excess of carbon incorporated therein. The product is subsequently heated to react the excess carbon within the compound with oxygen from the atmosphere to form carbon monoxide gas, which may be removed by an optional exhaust system.

Abstract: A high purity aluminum nitride is made by precipitating (CH.sub.3).sub.3 Al:NH.sub.3, washing it with hexane and pyrolyzing it to AlN. The precipitation is obtained by reacting a hexane solution of trimethyl aluminum with high purity anhydrous NH.sub.3(g), or by reaction Al(CH.sub.3).sub.3(g) and NH.sub.3(g) in a hexane solution, or by reacting Al(CH.sub.3).sub.3(g ) with NH.sub.3(1). The resulitng AlN is very pure and a density of 91.3% of theoretical has been achieved by pressing and sintering a pellet made from it as compared to a 89% theoretical density obtained by pressing and sintering a pellet made from commercial AlN powder.

Abstract: A method for producing an aluminum nitride powder of superior sinterability of which steps are providing an aqueous boehmite sol having a pH of 1.2 to 4.5, mixing a carbon source material to the sol and drying the mixture. The mixture is sintered in a non-oxidizing atmosphere containing nitrogen or in a nitrogen atmosphere and finally decarbonized to obtain an aluminum nitride powder. The carbon source material is preferably a mixture of an organic carbon source material and a solid carbon powder. A predetermined amount of alpha-alumina may be added to the mixture.

Abstract: An efficient, low-temperature process for the preparation of highly pure, free-flowing aluminum nitride powder without oxygen contamination, comprising the steps of:(1) forming a mixture of ##STR1## and (b) AlCl.sub.3 ;(2) reacting the mixture formed in step (1) at a temperature of from 0.degree. C. to 150.degree. C. and thereby forming ##STR2## (3) maintaining the Cl.sub.2 --Al--NH--Si(CH.sub.3).sub.3 formed in step (2) at a temperature of from 170.degree. C. to 200.degree. C. and thereby forming Cl--Al--NH and (CH.sub.3).sub.3 --SiCl; and(4) maintaining the Cl--Al--NH formed in step (3) at a temperature of at least 450.degree. C. and thereby forming H.sub.2, Cl.sub.2, and AlN.

Abstract: Method for making a ceramic mixture of boron and aluminum nitrides in the ratio of about 0.2 to 20 g atoms of aluminum per g atom of boron, and method for making shaped articles of the ceramic and of the intermediate from which the ceramic is prepared, comprising the steps (i) reacting a boron nitrogen compound with an organoaluminum compound in a suitable solvent to form a shapeable intermediate, and (ii) heating the intermediate at temperatures and under conditions to effect formation of the mixed nitrides.

Abstract: A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

Abstract: Novel self-supporting ceramic structures are produced by the oxidation reaction of a molten metal precursor with a vapor-phase oxidant to form an oxidation reaction product. Molten metal is drawn through the oxidation reaction product towards the oxidant to cause continued growth of the product at the interface between oxidant and previously formed product. This reaction or growth is continued to form a thick, self-supporting ceramic body. The resulting ceramic material of the polycrystalline growth product consists essentially of an oxidation reaction product and, optionally, one or more non-oxidized constituents of the metal precursor.

Abstract: An aluminum nitride ceramic is formed by pyrolyzing a poly-N-alkyliminoalane. A ceramic comprising a solid solution of silicon carbide and aluminum nitride is also formed by mixing a preceramic organosilicon polymer with a polyalkyliminoalane and pyrolyzing the mixed polymers composition to ceramic form.

Abstract: A process for preparing aluminum nitride powder, which comprises mixing (i) aluminum hydroxide powder, (ii) carbon powder or a substance capable of forming carbon powder by heating and (iii) at least one of additives selected from the group consisting of aluminum nitride powder, silicon nitride powder, silicon carbide powder and powder of substances capable of forming the powder corresponding to these powders, and baking the mixture thus obtained in a non-oxidative atmosphere containing nitrogen. The process is useful for preparing aluminum nitride powder having small particle size and small particle size distribution and also having a uniform shape of particles, at a lower temperature and in a shorter period of time.

Abstract: Nitrides and carbides are prepared by intercalating a monomer, a starting material of condensate, or a prepolymer into the interlamellar spaces or the vacant spaces of the crystalline structure of a natural mineral or an inorganic compound to prepare an intercalated compound and baking the intercalated polymer compound at a temperature in the range of 1100.degree.-1700.degree. C. under a nitrogen or reducing atmosphere. The present invention provides a method for readily preparing nitrides and carbides having the increased crystallinity at a low calcination temperature. Whiskers with larger diameters of 2 to 5 .mu.m can be prepared by adding carbon powder to the intercalated compound complex.