Liquid-phase sintering of SiC-based ceramics

Microstructural development and phase formation processes during sintering of silicon carbide based materials with AlN and Y(2)O(3) sintering additives were investigated. Densification of the materials occurred by liquid-phase sintering mechanism. Proportion of alpha- and beta -SiC powders in the initial mixtures was a variable parameter. Shrinkage behavior during sintering in interrelation with the starting composition of the material and the sintering atmosphere was investigated by differential dilatometry. Transformation-controlled grain growth mechanism similar to the one observed for silicon nitride based ceramics was established. Evolution of microstructure and phase composition was followed up by scanning electron microscopy and x-ray diffraction, respectively Possibility of in-situ platelet reinforced dense SiC-based ceramics fabrication with improved mechanical properties by means of sintering was shown.