Thermoelectric Properties of Silicon Carbide Sintered with Addition of Boron Carbide, Carbon, and Alumina

抄録

The thermoelectric properties were examined of SiC specimens prepared by mixing α-SiC powder with B₄C, C, and Al₂O₃ and then sintering at 2100°C. Sintered specimens containing Al₂O₃ up to 3% with 0.5% B₄C and 2.5% C exhibited the highest densities. The electrical conductivities of these specimens increased with the Al₂O₃ content up to 3%. In contrast, the Seebeck coefficients of these specimens decreased with the addition of 1% Al₂O₃, but then barely decreased with the further addition of Al₂O₃. The maximum value of the power factor, 9.43×10⁻⁴ W/mK² at 800°C, was obtained with specimens sintered with 3% Al₂O₃ as well as B₄C and C. These results showed that the power factor of SiC ceramics could be enhanced by adding proper amounts of B₄C, C, and Al₂O₃ into them.