Abstract
Pb-Sb-Se and its base alloys are promising thermoelectric materials. Its liquidus projection and the 400°C (673.2 K) isothermal section are determined. There are eight primary solidification phases. In addition to the three terminal phases, (Pb), (Sb) and (Se), there are PbSe, Sb 2 Se 3 , PbSb 2 Se 4 , Pb 6 Sb 6 Se 17 , and PbSb 5 Se 6 phases. The PbSb 5 Se 6 compound was found for the first time in this study. There are nine invariant reactions involving liquid. The reactions with the lowest and highest reaction temperatures are Liquid = PbSe + (Sb) + (Pb) at 250°C (523.2 K) and Liquid + PbSe + (Sb) = PbSb 5 Se 6 at 578.3°C (851.5 K), respectively. There are nine tie-triangles in the 400°C isothermal section including PbSe + (Sb) + Liquid, PbSe + PbSb 2 Se 4 + (Sb), PbSb 2 Se 4 + PbSb 5 Se 6 + (Sb), PbSb 2 Se 4 + PbSb 5 Se 6 + Sb 2 Se 3 , PbSb 5 Se 6 + Sb 2 Se 3 + (Sb), PbSe + Pb 6 Sb 6 Se 17 + PbSb 2 Se 4 , PbSe + Pb 6 Sb 6 Se 17 + Liquid, Pb 6 Sb 6 Se 17 + PbSb 2 Se 4 + Sb 2 Se 3 , and Pb 6 Sb 6 Se 17 + Sb 2 Se 3 + Liquid.