Thermodynamic assessment of the Te-X (X = As, Si, Co) systems

Abstract

Thermodynamic assessment of the Te-X (X = As, Si, Co) binary systems has been carried out using the CALculation of Phase Diagrams (CALPHAD) method. The thermodynamic parameters were evaluated based on the available experimental data in the literature. Thermodynamic models were constructed for all the phases in the three systems. The substitutional solution model was employed to describe the thermodynamic properties of solution phases including liquid, (Te), (As), (Si), and (Co). Due to the existence of associate species Si2Te3 and the difficulty of describing the liquid phase by the substitutional solution model, the associate model was adopted to describe the liquid phase in the Te-Si system. The intermetallic compounds in the Te-As and Te-Si systems were treated as stoichiometric phases and the compounds βCoTe and γCoTe2 in the Te-Co system were modeled by using sublattice model due to the homogeneity range. A set of self-consistent thermodynamic parameters for the Te-X (X = As, Si, Co) systems was obtained. Comparisons between the calculated results and experimental data available in the literature show that almost all the reliable experimental information can be satisfactorily accounted for by the present modeling.