Abstract
Bi 2 Te 3 is one of the most promising thermoelectric materials, and Sn is the primary constituent of most electronic solders. Knowledge of phase equilibria of the Sn-Bi-Te ternary system is important for thermoelectric applications. Twenty-seven Sn-Bi-Te alloys were prepared and equilibrated at 160°C and 500°C. The equilibrium phases were determined, and the isothermal sections were constructed based on three binary constituent phase diagrams and ternary phase equilibria results. No ternary compounds were observed in the Sn-SnTe-Bi region. The SnTe phase is very stable and has tie-lines with the Sn, liquid, and Bi phases at 160°C. At 500°C, in addition to the already known SnBi 2 Te 4 and SnBi 4 Te 7 ternary phases, two new ternary compounds (Sn 2 Bi 2 Te 5 and SnBiTe 2 phases) were found. SnTe and Bi 2 Te 3 have significant mutual solubilities, and the ternary compounds SnBi 2 Te 4 , SnBi 4 Te 7 , and Sn 2 Bi 2 Te 5 are all in the SnTe-Bi 2 Te 3 pseudobinary section. © 2011 TMS.