In Situ SiC-BN複合材料における相生成と緻密化に及ぼすY_2O_3-Al_2O_3助剤添加の影響

概要

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The effect of the addition of Y_2O_3-Al_2O_3 additive on the phase formation and densification process of in situ SiC-BN composite has been investigated. The in situ reaction started at 1450℃ despite the addition of Y_2O_3-Al_2O_3 additive. However, when Y_2O_3-Al_2O_3 was added the reaction was much faster and completed after hot pressing at 1700℃. In addition, dense material with well-crystallized SiC and BN grains could be obtained. It was found that denitrification occurred during the reaction process for both specimens with and without Y_2O_3-Al_2O_3 additive. However, denitrification occcurred continuously at temperatures higher than 1700℃ for the specimen without Y_2O_3-Al_2O_3 additive and eventually resulted in decrease of nitrogen content. The above results were explained based on the following mechanism, that is, the Y_2O_3-Al_2O_3 additive formed a Y-Al-Si-O liquid phase with SiO_2 present in Si_3N_4 raw powder, enhancing diffusion of the elements of the reactants.
社団法人日本セラミックス協会の論文
2001-01-01