Effects of Cu addition on the thermoelectric properties of hot-pressed β-FeSi2 with SiC dispersion

Abstract SiC dispersed β-FeSi 2 compounds were synthesized by hot-pressing with Cu addition. The effects of Cu addition on the thermoelectric performance of hot-pressed β-FeSi 2 with SiC dispersion were investigated. Cu addition increased the amount of residual e-phase, which deteriorated the thermoelectric power and thermal conductivity. The figure of merit Z of the SiC dispersed β-FeSi 2 with Cu addition decreased with increasing Cu content, indicating that Cu addition markedly ruined the effects of SiC dispersion. In order to reduce the amount of the e-phase, an excess of Si powder was added to the SiC dispersed samples with 2 mass% Cu. The Si addition effectively reduced the amount of the e-phase. The addition of 3 mass% Si was quite effective in improving the thermoelectric power and it did not have any influence on the electrical resistivity values. The figure of merit Z significantly increased on Si addition, and the SiC dispersed sample with 2 mass% Cu and 3 mass% Si addition showed almost the same values of Z as the SiC dispersed sample without Cu. From these results, even in the case of the sample with Cu addition, it was found that a high thermoelectric performance, as high as that of the SiC dispersed β-FeSi 2 without Cu, was obtained by using an excess addition of Si.