Development of a self-consistent thermodynamic database for Ga-In-Te system and experimental validation: a potential system for thermoelectric application

The Ga-In-Te alloy is one of the promising thermoelectric materials and its eutectic compositions can be expected to show improved thermoelectric behavior. In order to find the possible eutectic compositions in the ternary system, the thermodynamic modeling approach was considered based on the Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD) technique. Thermodynamic optimization and critical evaluation of the ternary Ga-In-Te system with the sub-binaries were performed using modified quasichemical model (MQM) for the liquid solution and compound energy formalism (CEF) for the solid solutions, respectively. By integrating the optimized sub-binaries, thermodynamic properties and phase diagram information in the ternary Ga-In-Te system were successfully reproduced. The asymmetric ternary interpolation method was applied to evaluate the Gibbs free energy of the ternary liquid solution. There were two line compounds of Ga2Te3-In2Te3 as a complete mutual solubility and InTe with limited solubility of Ga in the ternary system. The accuracy of the developed database was verified by comparing the measured phase transition temperatures with predicted phase diagrams and the microstructural analysis data with equilibrium cooling calculations.

Automated summary

In this study, thermodynamic modeling was used to find possible eutectic compositions in Ga-In-Te alloy. By optimizing sub-binaries and integrating thermodynamic properties and phase diagram information, the thermodynamic behavior of the system was successfully reproduced.