Thermoelectric Properties of SiB14-SiB6 Composites Prepared by Arc Melting and Annealing

Abstract

Si-B system composites were prepared by arc melting using Si and B powders and then annealed in an argon atmosphere. Arc-melted specimens consisted of mainly SiB14 and free Si. SiB6 phase formed at the boundary between SiB14 and free Si at content of 80 to 86mol%B by the annealing at 1670K. The lattice parameter of SiB14 increased with increasing annealing time due to the change of Si to B content ratio in SiB14 phase. The electrical and thermal conductivity of the composites decreased with increasing annealing time, but the Seebeck coefficient (α) showed maxima at the annealing time around 5.4ks. The greatest dimensionless figure-of-merit (ZT) value obtained in this study was 0.14 at T=1100K.