アーク溶解法により作製したB_4C-SiB_n-Si系複合セラミックスの微細組織と熱電特性

概要

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B-C-Si system composites were prepared by arc melting in argon atmosphere using B_4C, B and Si powders. The composites contained three phases : B_4C, SiB_n(n≩14)and free Si. The electrical conductivity(σ)of the composites in which the main phase was B_4C decreased with increasing SiB_n content, but slightly increased with increasing the solid solution of silicon. The Seebeck coefficient(α)of almost all the composites increased with increasing temperature, but B_4C containing a small amount of Si showed a maximum at 800 K. The composites in which the main phase was SiB_n containing free Si and B_4C had greater α values than B_4C. The thermal conductivity(κ)of the composites decreased with increasing temperature. The κ of the composites in which the main phase was B_4C increased and decreased by forming solid solutions of Si and B, respectively. The dimensionless figure-of-merit(ZT)increased with increasing temperature. The composites in which the main phase was SiB_n containing B_4C and several tens mol% Si had the greatest ZT value of 0.4 at 1100 K. This value is the largest level among high performance boron-rich borides.
社団法人日本セラミックス協会の論文
1998-02-01