Phase relations in the Pt-Bi-Te system at 350-550°C and 1 atm.

Phase equilibria in the system Pt-Bi-Te were studied by means of the evacuated silica glass tubes technique at 350, 450 and 550 °C.There are seven binary Pt phases that dissolve a third component: ss-PtTe 2 , ss-Pt 2 Te 3 , ss-Pt 3 Te 4 , ss-PtTe, ss-Pt 2 Bi 3 , ss-PtBi 2 , ss-PtBi.Ternary phases, including the maslovite analogue (PtBiTe), could not be obtained in the temperature range studied.The Te addition lowers the eutectoid decomposition temperature of Pt 2 Bi 3 by more than 200 °C.The ss-Pt 2 Bi 3 phase is stable with Te content of ~2-15 at.% at a temperature of 550 °C, with 7-10 at.% of Te at 450 °C and with ~11-12 at.% of Te at 350 °C.Temperature decrease from 550 to 350 °C yields the following changes in the phase relations in the system: appearance of stable Bi tellurides, reduction of the Bi and Te melt fields, alteration of the binary Pt phases homogeneity regions.Compositions of the synthesised samples were compared with those of natural Pt-bismuthotellurides.transition metals (Bi, Pb, Sn), metalloids (Sb, As, Te) and non-metals (Se, S), as well as an admixture