HIP焼結した窒化ケイ素の熱係数の温度依存性

概要

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Thermal diffusivity and conductivity as well as specific heat of capsule-HIPped Si_3N_4 with Y_2O_3 and Ai_3O_3 6mol%in total as additives were measured at different temperatures ranging from 100 to 1300 K. The isobaric specific heat Cp agreed with the isochoric specific heat C_v calculated by the Debye' s theory, assuming that silicon and vitrogen atoms are lattice dynamically equivalent. The Dulong-Petit's rule applied well to sintered Si_3N_4 at high temperatures and C_v≒25 J/(K・mol). The glassy phase quantity could be estimated by the difference of the measured specific-heat and the calculated specific heat at low temperatures. The specimens with higher thermal diffusivity and conductivity at low temperatures were those with higher β-phase fraction, larger particle size of raw Si_3N_4 and richer Y_2O_3 additive. For these specimens the thermal diffusivity and conductivity showed a larger temperature dependence.
社団法人日本セラミックス協会の論文
1989-02-01