Fabrication of Ag–Sn–Sb–Te based thermoelectric materials by MA-PAS and their properties

Starting from elemental powder mixtures of AgSn18SbTe20 and Sn50Te50, P-type AgSn18SbTe20 and Sn50Te50 bulk thermoelectric materials were fabricated by a combined process of mechanical alloying (MA) and plasma activated sintering (PAS). It was found that SnTe compound could be easily synthesized after milling only for 1 h. Prolonging the milling time, Ag and Sb atoms diffused into the lattice of the primary SnTe compound gradually and SnTe-based solid solution was formed. The electrical resistivity and Seebeck coefficient of the as-PASed samples were measured from 323 K to 723 K. The maximum power factor of 1.98 × 10−3 Wm−1 K−2 was obtained at 673 K for AgSn18SbTe20 and it was higher than that of the material with similar composition from previous published literature.

Research highlights▶ Single-phase SnTe compound can be obtained after milling for 1 h. ▶ Ag and Sb atoms enter into SnTe-based structure of AgSn18SbTe20. ▶ The maximum power factor of 1.98 × 10−3 Wm−1 K−2 was obtained at 723 K for AgSn18SbTe20. ▶ Ag and Sb codoping to SnTe compounds improved electrical properties.