INFLUENCE OF SILICA CONTENT ON LIQUID-PHASE SINTERING OF SILICON-CARBIDE WITH YTTRIUM-ALUMINUM-GARNET

Densification of SiC with oxide additives is affected mainly bg the am ounts of free C and SiO2 contained in the starting powders. In this st udy, the influence of oxidation of starting powders on densification w as investigated. Oxidation of SiC powders, prior to liquid phase sinte ring, increased the oxygen content and decreased the carbon content re markably, and led to higher sintered density for both alpha- and beta- Sic. Higher sintered density was attributed to the formation of liquid at lower temperatures and the suppression of reactions between the fr ee C and oxide additives.