Synthesis and thermoelectric properties of Mg2Si1-x Sn x solid solutions by microwave irradiation

In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Si1-x Sn (x) (x=0.2, 0.4, 0.6, 0.8) solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction (XRD). The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-x Sn (x) solid solutions are well formed with excessive content of 5% (molar fraction) Mg from the stoichiometric Mg2Si1-x Sn (x) under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-x Sn (x) solid solutions at about 500 K for x=0.6.