Process for making a reaction-sintered carbide-based composite body with controlled combustion synthesis

Claim 1

A process of preparing a sintered composite material comprised of alumina and silicon carbide, comprising the steps of sequentially: (a) providing a mixture comprised of from about 17 to about 34 percent of aluminum from about 11 to about 24 percent of amorphous carbon, and from about 55 to about 63 percent of silica, based on total weight of aluminum, carbon, and silica, wherein: 1. said aluminum has a specific surface area of from about 0.2 to about 1.1 square meters per gram, has a particle size distribution which ranges from about 4 to about 28 microns, and has at least 80 weight percent of its particles in the range of from about 6 to about 12 microns. 2. said amorphous carbon has a specific surface area of at least about 4 square meters per gram, and 3. said silica has a specific surface area of from about 1.2 to about 400 square meters per gram; (b) comminuting said mixture until a substantially single-phase material is produced; (c) granulating said single-phase material until substantially all of the particles in the material have a maximum dimension of from about 50 to about 2,000 microns; (d) forming said granulated material into a green body; (e) heating said green body to a temperature of from about 400 to about 600 degrees centigrade; (f) packing said green body in an inert powder, thereby forming an inert-powder/green body assembly; and (g) heating said inert-powder green body assembly to a temperature of from about 700 to about 900 degrees centigrade, thereby causing said green body to ignite, to combust, and to produce a sintered body.