Abstract: A composite is comprised of reinforcement fibers having a continuous coating with a first layer of a metal oxide wherein the metal is from the group consisting of aluminum, yttrium, titanium, zirconium, beryllium, silicon, and the rare earths, and a molten silicon infiltration formed silicon carbide matrix. The coating may have a second layer from the group consisting of rhodium, iridium, metal carbide, metal silicide, metal nitride, and metal diboride, on the metal oxide coating. The reinforcement fibers being fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A process for producing the fiber reinforced composite comprises depositing on the fibers a continuous coating comprised of the first layer of the metal oxide, and the second layer. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the fibers.

Abstract: Apparatus for close coupled atomization of melts of metals having high melting points with low superheats is taught. The atomization apparatus includes means for supplying melt to be atomized at the relatively low superheat, melt guide means for guiding the melt as a stream to an atomization zone and a gas supply and means for delivering the gas as a stream to the atomization zone where both the melt supply and gas supply to the atomization zone are in very close proximity. The melt supply has an inwardly tapered lower end disposed immediately above the atomization zone. The gas supply surrounds the melt guide tube and the gas is delivered as a jet against the melt emerging from the melt guide tube. The temperature of the gas impacting the end of the melt guide tube is very low because of the gas expansion.

Abstract: A composite is comprised of reinforcement fibers having a continuous coating of a metal diboride form the group consisting of titanium diboride, zirconium diboride, hafnium diboride, aluminum diboride, and mixtures thereof, and a molten silicon infiltration formed silicon carbide matrix. The reinforcement fibers are fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A method for forming the fiber reinforced composite comprises depositing a continuous coating of the metal diboride on the fibers. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.

Abstract: A protective coating for a reinforcement phase exposed to molten silicon or silicon alloy infiltrant comprises, an inner layer material resistant to reaction with the molten infiltrant, an interlayer of a reactive material that reacts with the infiltrant to form compounds having a melting temperature greater than the infiltrant, and an outer layer material resistant to reaction with the molten infiltrant. Materials resistant to reaction with molten silicon are a metal carbide from the group consisting of carbides of titanium, hafnium, zirconium, and tantalum; a metal nitride from the group consisting of nitrides of boron, silicon, aluminum, titanium, zirconium, hafnium, niobium, and tantalum; a metal boride from the group consisting of borides of titanium, zirconium, hafnium, silicon, and aluminum, or combinations thereof.

Abstract: A method of infiltration forming silicon carbide bodies having an improved surface finish comprises, infiltrating a porous carbonaceous preform with molten infiltrant to form a silicon carbide body. The body is heated in an inert atmosphere or vacuum to a temperature where the infiltrant is molten while the body is positioned in contact with an infiltrant wicking means. Preferably, the wicking means has infiltrant wicking capillaries at least as large as the infiltrant wicking capillaries in the body. Capillary force draws excess infiltrant on the surface of the body from the surface leaving the reaction formed silicon carbide body with a surface substantially free of excess infiltrant droplets.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having directly bonded to its outer surface wall a low density ceramic oxide shell.

Abstract: A ceramic composite is produced wherein the matrix is comprised of silicon nitride and cordierite and the reinforcing phase is comprised of Si-C-containing fibers.

Abstract: An integral transfer tube is produced comprised of a hollow high density ceramic oxide tube having its outer surface wall surrounded by a low density multilayered ceramic oxide shell, and having a heating element comprised of a heating wound portion and two end portions wherein the wound portion is intermediate the tube and the shell, and wherein at least a sufficient amount of the end portions are exposed for electrical attachment.

Abstract: Polycrystalline ceramic bodies having uniform transparent optical characteristics are produced by providing a green compact, presintering that compact at a temperature in the range from about 1,350.degree. C. to about 1,650.degree. C. until the closed porosity stage is reached, hot isostatic pressing the presintered compact to collapse substantially all pores disposed at grain boundaries and resintering the hot isostatically pressed compact at a temperature in the range from 1,700.degree. C.-1,950.degree. C. to cause grain growth under conditions in which pores, within those grains which are consumed by the growth of other grains, collapse as the grain boundary of the growing grain passes through the location of the pore in the smaller grain being consumed.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.

Abstract: An integral transfer tube is produced comprised of a hollow high density ceramic oxide tube having its outer surface wall surrounded by a low density ceramic oxide shell, and having a heating element comprised of a heating wound portion and two end portions wherein the wound portion is intermediate the tube and the shell, and wherein at least a sufficient amount of the end portions are exposed for electrical attachment.

Abstract: An integral transfer tube is produced comprised of a hollow high density ceramic oxide tube having its outer surface wall surrounded by a low density multilayered ceramic oxide shell, and having a heating element comprised of a heating wound portion and two end portions wherein the wound portion is intermediate the tube and the shell, and wherein at least a sufficient amount of the end portions are exposed for electrical attachment.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.

Abstract: An integral transfer tube is produced comprised of a hollow high density ceramic oxide tube having its outer surface wall surrounded by a low density ceramic oxide shell, and having a heating element comprised of a heating wound portion and two end portions wherein the wound portion is intermediate the tube and the shell, and wherein at least a sufficient amount of the end portions are exposed for electrical attachment.

Abstract: A ceramic composite containing less than 90% of a single phase silicon aluminum oxynitride and titanium nitride in an amount of up to about 10% by weight. Also disclosed are silicon nitride containing compositions for forming the composite and methods of producing the composite from the composition.

Abstract: A composite is produced by infiltrating the open pores of a polycrystalline silicon nitride body with a member selected from the group consisting of barium fluoride, calcium fluoride, magnesium fluoride, strontium fluoride, cerium fluoride, dysprosium fluoride, gadolinium fluoride, lanthanum fluoride, samarium fluoride, yttrium fluoride, and a mixture of said fluoride with a metal oxide.

Abstract: A composite is produced by infiltrating the open pores of a polycrystalline silicon nitride body with a member selected from the group consisting of barium fluoride, calcium fluoride, magnesium fluoride, strontium fluoride, cerium fluoride, dysprosium fluoride, gadolinium fluoride, lanthanum fluoride, samarium fluoride, yttrium fluoride, and a mixture of said fluoride with a metal oxide.

Abstract: A particulate mixture of ceramic powder, boron and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with boron producing a polycrystalline microcomposite comprised of a continuous phase of the boride of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.

Abstract: A particulate mixture of ceramic powder, free carbon and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with carbon producing a polycrystalline microcomposite comprised of a continuous phase of the carbide of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.

Abstract: A particulate mixture of ceramic powder, free carbon and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with carbon producing a polycrystalline microcomposite comprised of a continuous phase of the carbide of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.