Plasma etching of α-sialon ceramics

Plasma etching of β-Si 3 N 4 , α-sialon/β-Si 3 N 4 and α-sialon ceramics were performed with hydrogen glow plasma at 600°C for 10 h. The preferential etching of β-Si 3 N 4 grains was observed. The etching rate of α-sialon grains and of the grain-boundary glassy phase was distinctly lower than that of β-Si 3 N 4 grains. The size, shape, and distribution of β-Si 3 N 4 grains in the α-sialon/β-Si 3 N 4 composite ceramics were revealed by the present method