β-Si_3N_4結晶モフォロジーの制御とそのメカニズム(第1報):SiO_2とY_2O_3比の効果

概要

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The effect of Y_2O_3/SiO_2 ratio on grain growth of Si_3N_4 was systematically investigated using the "seed" fabrication method. The aspect ratio of β-Si_3N_4 crystals heat-treated with an additive composition of Y_2O_3:SiO_2=1:2 was found to be much smaller than that of Y_2O_3:SiO_2=2:1. It was confirmed that this was due to the difference in solubility of Si_3N_4 caused by the change of Y_2O_3/SiO_2 ratio of the liquid phase. The number of β-crystals originally contained in the raw Si_3N_4 powder changed very little in the Y_2O_3:SiO_2=1:2 composition, while it significantly decreased in the Y_2O_3:SiO_2=2:1 composition, which resulted in a considerable difference in aspect ratio. A mechanism for this enhanced solubility of Si_3N_4 in the liquid phase with high Y_2O_3/SiO_2 ratio was proposed.
社団法人日本セラミックス協会の論文
1999-10-01