Co-In-Sb Ternary System (II): Isoplethal Section and Thermodynamic Modeling

Thermoelectric devices have attracted worldwide attention, primarily due to their ability to convert heat directly into electricity. The ternary Co-In-Sb system with a CoSb₃ skutterudite phase is one of the most promising thermoelectric materials. In this paper, vertical section CoSb₃-InSb was experimentally determined with the aid of the X-ray diffraction method and electron probe microanalysis of samples equilibrated at 450 °C, 650 °C, 700 °C, 750 °C, 800 °C, 825 °C, and 850 °C. Based on information in the literature and data obtained in the current study, the thermodynamic model of the ternary Co-In-Sb system was developed. The proposed thermodynamic description agrees well with most available experimental data, except for some points from the primary solidification-phase experiment. The thermodynamic model can be applied in future studies on ternary thermoelectric materials or studies on higher-order systems where the Co-In-Sb system is involved.