β型窒化ケイ素の熱伝導率に及ぼす粒子径及び粒子内微構造の影響

概要

論文の詳細を見る
Silicon nitride containing Y_2O_3-Nd_2O_3 additives and one-dimensionally aligned β-Si_3N_4 whiskers was sintered at 2473 K with different sintering times, under 30 MPa in N_2, and its microstructure was investigated by scanning electron microscopy(SEM)and transmission electron microscopy(TEM). The results showed that the grain-growth behavior of one-directionally aligned Si_3N_4 grains obeyed the empirical grain growth law. SEM and TEM analyses suggested that the second phase, which consisted of Y, Nd, Si, O and N elements, existed as precipitated within elongated silicon nitride grains. The second phase precipitated in β-Si_3N_4 grains did not generate large elastic strain fields, resulting in negligible phonon-impurity scattering. The apparent thermal conductivity-grain size relationship in the obtained materials followed the Goldsmid and Penn equation, which predicts thermal conductivity to be proportional to the 1/2 power of grain size.
社団法人日本セラミックス協会の論文
1999-12-01