Synthesis and thermoelectric properties of Mg₂Si_1−xSn_x solid solutions by microwave irradiation

Abstract

In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg₂Si_1−xSn_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 Mg₂Si_1−xSn_x solid solutions are well formed with excessive content of 5% (molar fraction) Mg from the stoichiometric Mg₂Si_1−xSn_x under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg₂Si_1−xSn_x solid solutions at about 500 K for x=0.6.

Keywords

Mg₂Si_1−xSn_x / thermoelectric material / solid solution / microwave synthesis

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