Abstract: A composition containing at least 70 weight percent of a beta-prime sialon compound and at least about 27 weight percent of a solid solution is disclosed. The solid solution contains from 2 to 50 weight percent of alpha silicon nitride, from 0.5 to 14 weight percent of aluminum nitride, and from 97.5 to 36 weight percent of alpha alumina.

Abstract: A precursor material is disclosed. This precursor material is comprised of at least about 16 weight percent of beta-sialon, from about 54 to about 28 weight percent of alumina, from about 0 to about 8 weight percent of aluminum nitride, from about 0 to about 25 weight percent of silicon nitride, and from about 30 to about 24 weight percent of free silicon.

Abstract: There is disclosed a process in which a transition metal compound is mixed with silica until a specified density of intimate contact points is produced in the mixture. To this mixture is then added a reducing agent. Thereafter, a reinforcing agent is intimately dispersed throughout the mixture, the mixture is formed into a green body, and it then is ignited.

Abstract: A process for heat-treating a composite material is disclosed. The composite material contains alumina, free silicon, and a beta-sialon material of the formula Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, wherein z is from 2.5 to 3.5. In the heat treatment process, the composite material is subjected to temperatures of 800-1,000 degrees centigrade, 1,240 to 1,260 degrees centigrade, and 1,400 to 1,450 degrees centigrade for various times and under specified conditions.

Abstract: There is disclosed a process for preparing a sintered ceramic composite which is comprised of alumina and metal carbide. In the first step of this process, a mixture of silica, aluminum material, and carbon is comminuted until a substantially single-phase material is produced. In the second step of the process, the single phase material is granulated and formed into a green body. Thereafter, the green body is preferably packed in inert powder, placed into a closed reactor, and ignited.

Abstract: There is disclosed a titanium carbide/alumina composite material which contains from about 44 to about 54 weight percent of titanium carbide, from about 45 to about 53 weight percent of alumina, and less than 2 weight percent of titanium nitride, titanium oxide, titanium, or mixtures thereof.The total amount of carbon in the titanium carbide component of the composite is least 19 weight percent. However, the amount of free carbon in this component is less than about 0.5 weight percent.

Abstract: A process for preparing a ceramic composite material containing alpha silicon carbide whiskers is disclosed.In the process, a slurry containing non-aqueous liquid and aluminum material, amorphous carbon, and silica is provided. This slurry is thereafter pelletized, the pellets are dried, the dried pellets are preheated, and the preheated pellets are then ignited. The ignited pellets undergo an exothermic reaction, forming the composite containing alpha silicon carbide whiskers.The composite material is heat-treated by first heating it to a temperature of 900-1100 degrees centigrade at a rate of 8-15 degrees per minute, and then heating it to a temperature of 1,250-1,350 degrees centigrade at a rate of 2-5 degrees per minute.

Abstract: A novel composite mateial consisting of at least 70 weight percent of single-phase beta sialon and at least 20 weight percent of alpha-alumina is disclosed. The beta-sialon is of the formula Si.sub.6-z Al.sub.z -.sub.z N.sub.8-z, wherein z is from 2.5 to 3.5. The composite material contains no silicon nitride. Sintered products made from such composite material contain no glassy phase, contain no silicon nitride, and have superior thermal and mechanical properties.

Abstract: A process for preparing molybdenum disilicide or a molybdenum disilicide/alumina composition is provided. In the first step of this process, a mixture containing molybdenum oxide, silica, aluminum and/or magnesium, and inorganic diluent is provided; the mixture may also contain organic surfactant and/or organic binder. In the second step of the process, the mixture is ignited, thereby causing a self-propagating reaction to occur. Thereafter, the combusted product is cooled and then washed with water, preferably until it contains less than about 0.1 percent of inorganic diluent. When the combusted product contains magnesia, the magnesia is leached from the product by treatment with nitric acid and sodium hydroxide.

Abstract: A process for preparing a ceramic composite material containing alpha silicon carbide whiskers is disclosed.In the process, a slurry containing non-aqueous liquid and aluminum material, amorphous carbon, and silica is provided. This slurry is thereafter pelletized, the pellets are dried, the dried pellets are preheated, and the preheated pellets are then ignited. The ignited pellets undergo an exothermic reaction, forming the alpha silicon carbide whiskers.

Abstract: A process for preparing a ceramic composite which is comprised of alpha silicon carbide whiskers and alpha aluminum oxide powder is disclosed. In the first step of this process, there is provided a slurry comprised of from about 80 to about 92 volume percent of solid material and from about 20 to about 8 volume percent of a non-aqueous liquid. In this slurry, the solid material comprises from about 30 to about 38 weight percent of aluminum material, from about 10 to about 14 weight percent of amorphous carbon, and from about 52 to about 62 weight percent of silica.The slurry provided in the first step of this process is thereafter passed through a twin-deck sieve to pelletize it.The pellets are then dried to a moisture content of from about 0.1 to about 1.

Abstract: A process for preparing a ceramic composite with improved properties is disclosed. A material which contains at least 85 percent of a mixture of silicon carbide and alumina is heated to a temperature of from about 350 to about 500 degrees centigrade and, after it reaches this temperature, maintained there for at least 5 minutes. Thereafter, the temperature of the material is raised to 1,250-1,350 degrees centigrade and, after reaching this temperature, the material is maintained there under a pressure of from about 5 to about 15 p.s.i. for at least 30 minutes. Thereafter, the temperature of the material is raised to 1,650-1,750 degrees centigrade, and it is thereafter maintained at such temperature for from about 30 to about 90 minutes.

Abstract: A process for pressing a ceramic composite which is comprised of alpha silicon carbide whiskers and alpha alumina oxide is disclosed. The composite material is blanketed with nitrogen, heated to a temperature of from about 1,250 to about 1,450 degrees centigrade, thereafter heated to a temperature of from about 1,650 to about 1,900 degrees centigrade while pressure on the system is increased, and thereafter maintained under specified temperature and pressure conditions for from about 30 to about 90 minutes.