抄録
Dimagnesium silicide (Mg2Si) is a promising thermoelectric material for energy conversion over intermediate temperature range (300 to 600°C). This material has advantages of the constituent elements in abundance in the earth's crust and of the nontoxicity of its processing by-products as an environmental symbiosis thermoelectric semiconductor. However, there are few research reports about this material for improving thermoelectric performance because of difficulty of its synthesis. In this study, Mg2Si was synthesized from Mg and Si powders by a liquid-solid phase reaction (LSPR) method, which is effective in synthesizing a compound from the two elements having sufficiently different melting points. The powder synthesized by LSPR method was compacted and then sintered by a pulse discharge sintering (PDS) process. Influence of sintering conditions on thermoelectric properties of Mg2Si was investigated. The thermoelectric properties of each sintered sample were measured at temperature of RT to 600°C. The thermoelectric properties of the sintered sample were, however, strongly affected by the sintering temperature and/or the sample density. The sample sintered at 730°C for 30 min under 60 MPa had the maximum dimensionless figure of merit of 0.27 at 516°C. This value is higher than the previous report.
