粒成長が窒化ケイ素の熱伝導率に及ぼす影響

概要

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Thermal conductivity of sintered silicon nitride has been improved by grain growth of β-Si_3N_4. β-Si_3N_4 containing 0.5 mol% Y_2O_3 and 0.5 mol% Nd_2O_3 was gas-pressure sintered at 1973 to 2473 K and the microstructures and the thermal conductivities were investigated. The materials sintered at temperatures higher than 2173 K had a microstructure of "in-situ composite" with smaller β-Si_3N_4 matrix grains and a small amount of elongated β-Si_3N_4 grains. The grain size increased with increasing sintering temperature. Room temperature thermal conductivity increased with increasing sintering temperature ; 122 W・m^<-1>・K^<-1> was produced by sintering at 2473 K - this value was about two times higher than the values reported up to this time. Higher thermal conductivities were established by growth of Si_3N_4 grains and decrease in the amount of two-grain junctions.
社団法人日本セラミックス協会の論文
1996-01-01