金属ホウ化物を添加したSiCの焼結

概要

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α(6H)-SiC powders mixed with 11 types of metal boride, B and C were sintered at high temperatures (1800-2200°C for 30min). MoB, NbB_2, TaB_2, TiB_2, VB_2, WB, and ZrB_2 promoted the densification of SiC powder and sintered SiC had a high fracture toughness (4.07-4.75Mpa・m^<1/2>). The addition of metal boride enabled us to control the grain growth and densify SiC powder containing a fairly large amount of B. Metal borides dispersed in SiC grains, precipitated in triple points, and appeared to obstruct grain growth and crack propagation. CaB_6, CrB, LaB_6, and YB_6 did not promote sintering of SiC powder. These latter metal borides resulted in highly exaggerated grain growth and the SiC powder became porous after sintering. The starting 6H-SiC powder tended to be partially transformed into a 4H polytype which was accompanied by grain growth.
社団法人日本セラミックス協会の論文
2003-12-01