還元窒化法によるAlN粉末の合成 : 窒化反応に及ぼす各種添加物の影響

概要

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The effect of additives on carbothermal reduction-nitridation was investigated for the preparation of AlN powders from the Al_2O_3-C-N_2 system. According to the role of additives in nitridation, they were divided into three categories "promote", "have no effect" and "disturb". In particular, CaF_2 was an excellent nitridation promoter providing spherical AlN particles. The apparent activation energy of nitridation for CaF_2 addition was 190 kJ/mol, while those for Y_2O_3, Yb_2O_3 and without additive were around 250 kJ/mol. CaF_2, Y_2O_3, Yb_2O_3 and transition metal compounds strongly affected AlN grain morphologies, supplying spherical and rod-like shapes of AlN. It was estimated that the reduction-nitridation proceeds through the formation of intermediates like CaF_2・5Al_2O_3 and Y-aluminates.
社団法人日本セラミックス協会の論文
1993-04-01