Abstract: A fine powder of aluminum nitride having an average particle diameter of not more than 2 microns and comprising at least 94% by weight of aluminum nitride, at most 3% by weight of bound oxygen and at most 0.5% by weight as metal of metal compounds as impurities.The fine aluminum nitride powder is prepared from a fine alumina powder and a fine carbon powder as starting materials.The fine aluminum nitride powder provides a sintered body having a high purity and a high density such as at least 2.9 g/cm.sup.3.The fine aluminum nitride powder is also useful as a raw material for alpha-Sialon, beta-Sialon and AlN polytypes, as an addition aid in various ceramics.

Abstract: A method for making an aluminum nitride powder comprises atomizing a molten aluminum into a nitriding atmosphere of N.sub.2 gas of elevated temperature and solidifying the finely divided liquid particles of aluminum which have been nitrided.

Abstract: A method for making ultra-fine ceramic particles, in which metal powder constituting a portion of the ultra-fine ceramic particles intended for production is injected at a rate of not less than 70 grams per minute into a plasma jet so that the metal powder is vaporized. The vaporized metal powder is then mixed with a reactive gas, which includes an element consituting the other portion of the ultra-fine ceramic particles, filled in the surrounding area of the plasma jet, and thereby the vaporized metal powder and the reactive gas produce a synthetic reaction. The ultra-fine ceramic particles are produced continuously because of the reaction flame.

Abstract: A component for an aluminum production cell comprising a refractory matrix having a rigid porous structure substantially filled with aluminum.

Abstract: An improved method of manufacturing a composite structure of ceramic material reinforced by refractory fibers is disclosed, whereby the fibers are first embedded in a slip of the ceramic material containing a synthetic resin with good ceramic and fiber wetting properties and a solvent of said resin, the liquid phase is thereafter eliminated from the slip by drying, the synthetic resin is driven from the formed structure by heating, and the fiber-reinforced ceramic material is sintered. The improvement consists in avoiding the use of costly aluminum-nitride powder by initially incorporating an aluminum powder in the slip along with the resin solvent and nitriding the powder in the structure, after drying and firing, but before sintering.

Abstract: A process for producing a polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by line ABCDEFA but not including lines CD and EF of FIG. 1, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.0 W/cm.multidot.K at 22.degree. C. which comprises forming a mixture comprised of aluminum nitride powder and an yttrium additive selected from the group consisting of yttrium, yttrium hydride, yttrium nitride and mixtures thereof, said aluminum nitride and yttrium additive having a predetermined oxygen content, said mixture having a composition wherein the equivalent % of yttrium, aluminum, nitrogen and oxygen is defined and encompassed by line ABCDEFA but not including lines CD and EF in FIG. 1, shaping said mixture into a compact and sintering said compact at a temperature ranging from about 1850.degree. C. to about 2170.degree. C.

Abstract: The process comprises forming a mixture comprised of aluminum nitride powder and free carbon wherein the aluminum nitride has a predetermined oxygen content higher than about 0.8% by weight and wherein the amount of free carbon reacts with such oxygen content to produce a deoxidized powder or compact having an oxygen content ranging from greater than about 0.35% by weight to about 1.1% by weight and which is at least 20% by weight lower than the predetermined oxygen content, heating the mixture or a compact thereof to react the carbon and oxygen producing the deoxidized aluminum nitride, and sintering a compact of the deoxidized aluminum nitride producing a ceramic body having a density greater than 85% of theoretical and a thermal conductivity greater than 0.5 W/cm.multidot.K. at 22.degree. C.

Abstract: Precursors, particularly of non-oxide ceramics, are prepared by special seeding, under carefully controlled conditions. Such procedures can lead to the preparation of unique powders, which may be useful, for example as abrasives, or further processed in special manner to prepare a variety of metal substances. Such procedures can permit final firing to sintered product.

Abstract: The process comprises forming a mixture comprised of aluminum nitride powder and free carbon wherein the aluminum nitride has a predetermined oxygen content higher than about 0.8% by weight and wherein the amount of free carbon reacts with such oxygen content to produce a deoxidized powder or compact having an oxygen content ranging from greater than about 0.35% by weight to about 1.1% by weight and which is at least 20% by weight lower than the predetermined oxygen content, heating the mixture or a compact thereof to react the carbon and oxygen producing the deoxidized aluminum nitride, and sintering a compact of the deoxidized aluminum nitride producing a ceramic body having a density greater than 85% of theoretical and a thermal conductivity greater than 0.5 W/cm.K at 22.degree. C.

Abstract: A process for fabricating aluminum nitride needles, the process utilizing moderate furnace temperatures (950.degree. C.-1000.degree. C.) and low toxicity reactants (i.e. NH.sub.3 and Al). Argon gas and ammonia gas are mixed and flowed over the heated aluminum and the aluminum nitride needles grow at the upstream end of the hot zone of the furnace.

Abstract: Solid aluminum nitride, deposited for example, in epitaxial layers, is prepared by reacting aluminum and selenium to form aluminum monoselenide, and transporting the aluminum monoselenide in an inert carrier gas to a heated deposition zone where it is contacted with and reacts with nitrogen to give the aluminum nitride, the carrier gas flushing away elemental selenium also produced in the deposition zone.

Abstract: Electronic grade aluminum nitride semiconductor material may be uniformly nucleated and epitaxially formed on an aluminum oxide substrate by reacting aluminum oxide or aluminum nitride with nitrogen in the presence of carbon.

Abstract: An ultraviolet light emitting diode array of aluminum nitride grown on a sapphire substrate is fabricated by sputtering a preliminary layer of aluminum nitride onto a sapphire substrate, then placing said coated substrate in contact with a source of aluminum nitride and heating said composite in a particular atmosphere, resulting in the deposition of layers of aluminum nitride onto said coated substrate.

Abstract: The preparation of metal and metalloid carbides, borides, nitrides silicides and sulfides by reaction in the vapor phase of the corresponding vaporous metal halide, e.g., metal chloride, with a source of carbon, boron, nitrogen, silicon or sulfur respectively in a reactor is described. Reactants can be introduced into the reactor through a reactant inlet nozzle assembly. Inhibition and often substantial elimination of product growth on exposed surfaces of such assembly is accomplished by introducing the corresponding substantially anhydrous hydrogen halide, e.g., hydrogen chloride, into the principal reactant mixing zone.

Abstract: A method of manufacturing an airtight-sealed system comprising one or more molten alkalifluorides in the operating condition.The corrosive action of oxygen present in the melt is prevented by adding metallic aluminium and/or zinc to the melt.

Abstract: A method for growing single crystals which utilizes calcium nitride as a solvent system in the molten solution growth of bulk aluminum nitride crystals.

Abstract: Solid compositions, stable at ambient temperatures, which generate hydrogen as when heated to initiate the reaction between the components of the composition.The compositions comprise certain ammonium salts such as NH.sub.4 Cl and complex hydrides such as LiAlH.sub.4 and NaAlH.sub.4 or certain hydrazine derivates such as N.sub.2 H.sub.6 Cl.sub.2 and complex hydrides such as NaBH.sub.4.