焼結助剤の異なる炭化ケイ素の破壊表面エネルギーと微構造組織

概要

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This study was carried out to clarify the relationship between microstructures and mechanical properties of SiC sintered with Al_2O_3 additive (1960℃ for 2 h and 1980℃ for 4 h) and with B and C additives. Fracture surface energy, y_i, for crack initiation and work of fracture surface energy, y_<wof>, for crack propagation were selected as suitable parameters for screening the mechanical properties. y_i was measured by both indentation fracture (IF) and Chevron notch three-point bend methods. The Chevron notch method was also performed to measure y_<wof>. y_i measured by the IF method depended on the applied load and the relationship between the load and y_i differed among specimens with different microstructures. It was found that the y_i measured at a high load is about the same as that measured by the Chevron notch method for all the specimens. Both y_i, and y_<wof> of SiC sintered with Al_2O_3 additive were higher than those of SiC sintered with B and C additives. y_i and y_<wof> of SiC sintered with B and C were about the same, while y_<wof> of SiC sintered with Al_2O_3 additive was higher than y_i. Sintering aids, grain size and morphology affected the crack propagation behavior.
社団法人日本セラミックス協会の論文
2002-09-01