Thermoelectric properties and microstructure of Mg3Sb2

Mg3Sb2 has been prepared by direct reaction of the elements. Powder X-ray diffraction, thermal gravimetric, differential scanning calorimetery, and microprobe data were obtained on hot pressed samples. Single phase samples of Mg3Sb2 were prepared and found to contain oxygen at the grain boundaries and to lose Mg and oxidize at temperatures above 900 K. Thermoelectric properties were characterized by Seebeck, electrical resistivity, and thermal conductivity measurements from 300 to 1023 K, and the maximum zT was found to be 0.21 at ∼875 K.

Dimensionless figure of merit for Mg3Sb2 hot pressed and sintered at 873 K. The inset illustrates the crystal structure of Mg3Sb2 along the [100] direction (white=Mg, black=Sb).Figure optionsDownload as PowerPoint slide