FORMATION OF SOLID-SOLUTIONS BETWEEN SIC AND ALN DURING LIQUID-PHASE SINTERING

A 2H-solid solution between SiC and AIN, along with a dispersion of Si C, was prepared by Liquid-phase sintering, and the mechanism of solid solution formation between SiC and AlN was investigated from studies o f the microstructures of the sintered body. The SiC-AlN composite micr ostucture was composed of isolated SiC particles, the 2H-solid solutio n of spherical shape, and an irregular shaped phase which was liquid a t high temperature, The grain morphology of the 2H-solid solution phas e was almost the same with equiaxed grains of 2 to 3 mu m in diameter. The AIN content in the 2H-solid solution was higher than that of SiC, A few 2H-grains showed a core-rim structure and a difference in Si co ntent between core and rim. The Si content in the rim was higher than that in the core. Al2O3 grains surrounded by YAG were found to be embe dded in the 2H grains, The 2H-solid solution formed during liquid-phas e sintering occurs via a nucleation and growth process.