β型窒化ケイ素焼結体中のコア/リム構造の電子顕微鏡観察

概要

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Fine β-Si_3N_4 powders containing 5 mass% of large β-Si_3N_4 particles were gas pressure sintered at 1900℃ for 4h using Y_2O_3 and Al_2O_3 as sintering aid. A corel rim structure was observed by scanning and transmis sion electron microscopy. The core was pure P Si_3N_4 and the rim was β-sialon. The electron dffraction pat terns indicated that the core and rim had the same orientation, showing that the rim was epitaxiany grown on the core. Lattice mismatch was observed at the core/rim boundary by HREM. These results show that the relatively large β-Si_3N_4 particles in raw materi al powder acted as seeds for grain growih and that the rim was formed by epitaxial precipitation from liquid containing Al. When β-Si_3N_4 is used as the raw materi al powder, the particle size distribution is especially irnportant for the developnrent of in situ conrposite microstructure.
社団法人日本セラミックス協会の論文
1994-09-01