Method of preparing refractory silicon carbide composites and coatings

Abstract

A carbonaceous preform is infiltrated with a silicon melt alloyed with at least one element which is substantially insoluble in silicon carbide and which forms refractory phases. The resulting silicon carbide composite has substantially no free silicon. Silicides of the alloying elements are a suitable refractory phase. Suitable alloying elements which form refractory silicides include Mo, W, Re, Hf, Zr, Cr, B, and Ti. The carbonaceous preform may include graphite particulates, carbon particulates, porous carbon skeletons, carbon-carbon composites, carbon fibers, and graphite fibers. Particulates may be incorporated into the preform for the purpose of improving mechanical properties. Suitable particulates include refractory metals, carbides, nitrides, borides, silicides, and oxides. Fiber-reinforced composites can be produced by incorporating whiskers, chopped fibers, or continuous fibers of a refractory material into the preform. The refractory phase in the composite has a beneficial effect on the high temperature mechanical properties, such as the hardness, strength, toughness, and creep resistance of the silicon carbide composites.

Dependencies are inferred from the claim text.