Microstructures and liquidus projection of the ternary Ag-Sb-Te system

Ag-Sb-Te alloys are important for thermoelectric applications. Fifty-one Ag-Sb-Te ternary alloys were prepared, and their primary solidification phases were analyzed. The liquidus troughs of the liquidus projection of the ternary Ag-Sb-Te system are determined based on the experimental results and the phase diagrams of the three binary constituent systems. There are 13 primary solidification phase regions. In addition to the three terminal solid solution phases and nine binary compounds, there is one ternary compound, AgSbTe2. A unique microstructure with bright spherical phases uniformly dispersed in a matrix caused by a miscibility gap in the liquid phase is found in the gamma-Ag2Te primary solidification phase regime. A very fine microstructure with nanometer size Ag2Te is also observed, resulting from the class I reaction, liquid = delta + Ag2Te + AgSbTe2, at 496.5 degrees C, and the liquid composition of Ag-40.0 at%Sb-36.0 at%Te. (C) 2010 Elsevier B.V. All rights reserved.