Thermoelectric properties of Mg₂Si_1-xSn_x synthesized by bulk mechanical alloying

Bulk mechanical alloying (BMA) has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg₂Si _1-xSn_x (x = 0, 0.2, 0.4, 0.6, 0.8, 1) from element-powders at the room temperature in a relatively short time. The electrical conductivity, the Seebeck coefficient and the thermal conductivity of the Mg₂Si_1-xSn_x are quite sensitive to the x-content. With the x-content rising, the electrical conductivity increases. When x = 0.6, it reaches the lowest and Mg₂Si shows an n-type of semi-conducting. However, when x = 0.2 and T > 525 K, the Seebeck coefficient of the samples will change the opposite way. While x≥0.4, the samples present a p-type of semi-conducting. The figure of merit, Z of Mg ₂Si_1-xSn_x will be obtained in the range from 300 K to 700 K. When x = 0.6, Z proves to be higher than that of other samples at 300 K≤T≤650 K.