Preparation of B₄C-TiB₂ System Composites by Arc Melting and their Thermoelectric Properties

Abstract

B₄C-TiB₂ quasi-binary composites were prepared by arc melting in argon atmosphere using B₄C and TiB₂ powders. Uniform lamella texture indicating eutectic reaction was observed at 25mol%TiB₂ in the quasi-binary system. The electrical conductivity of the B₄C-TiB₂ composites significantly increased with increasing TiB₂ content. The thermal conductivity (κ) of the composites containing 2mol%TiB₂ was slightly smaller than that of B₄C, but the κ values increased with increasing TiB₂ content at more than 6mol%. The Seebeck coefficient of B₄C-TiB₂ composites showed maxima at 6mol%TiB₂. The thermoelectric figure-of-merit (Z) values exponentially increased with increasing temperature, showing maxima at 6mol%TiB₂. The greatest ZT values obtained in the present study was 0.55 at T=1100K for the composite containing 6mol%TiB₂.