Re-investigation of the phase constitution of the system Pt-Te

Abstract

The phase relations of the system Pt-Te have been investigated using the conventional sealed-capsule technique. The identification of phases present in the reaction products was made by reflected light microscopy, X-ray diffraction, and electron probe microanalysis. Four binary phases were confirmed to exist in the system: PtTe., Pt₃Te₄, Pt₂Te₃ and PtTe₂. The composition of all these appears to be constant without showing any appreciable compositional range. The Pt₂Te phase was not found in this study. The Te content in platinum and the Pt in tellurium in solid solution are negligible, less than 0.5 at.% up to 1000°C. The eutectic point between Pt and PtTe is near at 40 at.% Te and at 870°C. The Pt₂Te₃ phase is stable up to about 675°C, whereas the melting point of the Pt₃Te₄ phase is apparently above 1000°C. The most part of liquidus curve between PtTe₂ and Te exists above 1000°C. Physico-chemical properties of Pt-Te phases obtained in this study are given. The revised phase diagram of the Pt-Te system is proposed from this study.