高収率ポリカルボシランを添加したアルミナ焼結体の機械特性及び微構造

概要

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Effect of polycarbosilane(PC), with high ceramic yield of 85%, added to Al_2O_3 was investigated. Green density of the Al_2O_3 powder compact tincreases by the PC coating. Al_2O_3 ceramics containing 5 to 10 vol% SiC derived from PC were fabricated by the hot-press sintering at temperatures between 1600°C and 1800°C. After hot-pressing at 1600°C, almost all PC-derived SiC-phase exists at grain boundaries as fine crystalline grains, which results in a significant decrease in Al_2O_3 grain-growth rate and in a low fraction of porosity as well. Some of the PC-derived SiC-phase may be drawn inside the Al_2O_3 grains during grain growth at 1800°C to form intragranular SiC nanoparticles. Four-point bending strength of Al_2O_3 was increased, and the scatter in bending strength values significantly decreased by the PC coating. Intragranular fracture mode was observed in the PC-coated Al_2O_3 composite, while Al_2O_3+SiC poweder composite exhibited intergranular fracture.
社団法人日本セラミックス協会の論文
1999-12-01