Preparation of Mg2Si1−xSnx by Induction Melting and Spark Plasma Sintering, and Thermoelectric Properties

Sn-doped, Mg2Si1−xSnx (x = 0 to 0.6) bulk alloys were prepared using Mg and Sn ingots as raw materials by suspended induction melting combined with the spark plasma sintering method, and the effects of Sn doping on thermoelectric transport properties were studied systematically. The results showed that Mg site vacancies caused by evaporation during the reaction process were filled by excess Mg addition (108 wt.% of the stoichiometric ratio of Mg2Si). The resulting alloy samples were found to be single phase and relatively dense (above 98%). n-Type semiconducting characteristic of Sn-doped Mg2Si1−xSnx alloy was observed, and the electrical resistivity of all samples decreased with increasing temperature. The absolute Seebeck coefficient increased and the thermal conductivity was not changed significantly within the experimental Sn doping range. The dimensionless figure of merit (ZT) for Mg2Si0.4Sn0.6 alloy reached its highest value of 0.25 at 400°C.