Solid State Synthesis and Thermoelectric Properties of Mg-Si-Ge System

摘要

Thermoelectric materials, Mg2Si1-xGex (x=0, 0.2, 0.4, 0.6, 0.8, 1), have been prepared by bulk mechanical alloy-ing (BMA) and hot pressing (HP). The electrical conductivity, Seebeck coefficient and thermal conductivity weremeasured from room temperature up to about 700 K. The electrical conductivity of all the samples increases withincreasing temperature, while the Seebeck coefficient and thermal conductivity decrease with increasing temperature.Mg2Si and Mg2Si0.8Ge0.2 possess negative type of conductivity, while for other compounds it is positive. At thesame time, the effect of hot processing condition on thermoelectric properties was also investigated. The maximumfigure of merit of Mg2Si0.6Ge0.4 was obtained with the processing parameter of BMA at 600 cycles and hot pressingat 773 K and 1 GPa for 1 h.