Experimental study of the phase diagram and thermodynamic properties of the Tl-Sb-S system

Abstract

Phase equilibria in the ternary Tl-Sb-S system have been experimentally re-investigated over the entire composition range by means of powder X-ray diffraction (PXRD), differential thermal analysis (DTA) and electro-motive force measurements (EMF) applied to equilibrated alloys. Four vertical sections and isothermal section at 300K as well as the liquidus surface projection were constructed based on the experimental data. The homogeneity ranges and primary crystallization fields of all phases as well as the types and temperatures of non- and monovariant equilibria were determined. The existence of the earlier reported ternary TlSb5S8, TlSb3S5, TlSbS3, TlSbS2, Tl3SbS4 and Tl3SbS3 compounds were confirmed, whereas the two compounds, Tl2SbS2 and Tl4SbS2 were not found during the present investigation. The standard formation thermodynamic functions and standard entropies of the confirmed compounds were calculated based on EMF measurements data.