Thermodynamic modelling of the ternary Bi-Ga-Te system for potential application in thermoelectric materials

Kumar, Bhupender; Tiwary, Chandra Sekhar; Paek, Min-Kyu; Paliwal, Manas

doi:10.1016/j.calphad.2021.102326

Cited by 12 publications

(2 citation statements)

References 63 publications

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“…The composition of maximum SRO in each binary subsystem is estimated by ratio of the coordination numbers Z B /Z A . In this study, all the coordination numbers are set to 6, except Z Te GaTe = 4 to have a maximum SRO composition, X Te = 0.6 in the Ga-Te binary system [29].…”

Section: Liquid Solutionmentioning

confidence: 99%

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Thermodynamic Optimization of the Ternary Ga-Sn-Te System Using Modified Quasichemical Model

Kumar

Paliwal

Tiwary

et al. 2021

Metals

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Thermoelectric (TE) materials are of great interest to many researchers because they directly convert electric and thermal energy in a solid state. Various materials such as chalcogenides, clathrates, skutterudites, eutectic alloys, and intermetallic alloys have been explored for TE applications. The Ga-Sn-Te system exhibits promising potential as an alternative to the lead telluride (PbTe) based alloys, which are harmful to environments because of Pb toxicity. Therefore, in this study, thermodynamic optimization and critical evaluation of binary Ga-Sn, binary Sn-Te, and ternary Ga-Sn-Te systems have been carried out over the whole composition range from room temperature to above liquidus temperature using the CALPHAD method. It is observed that Sn-Te and Ga-Te liquids show the strong negative deviation from the ideal solution behavior. In contrast, the Ga-Sn liquid solution has a positive mixing enthalpy. These different thermodynamic properties of liquid solution were explicitly described using Modified Quasichemical Model (MQM) in the pair approximation. The asymmetry of ternary liquid solution in the Ga-Sn-Te system was considered by adopting the toop-like interpolation method based on the intrinsic property of each binary. The solid phase of SnTe was optimized using Compound Energy Formalism (CEF) to explain the high temperature homogeneity range, whereas solid solution, Body-Centered Tetragonal (BCT) was optimized using a regular solution model. Thermodynamic properties and phase diagram in the Ga-Sn-Te and its sub-systems were reproduced successfully by the optimized model parameters. Using the developed database, we also suggested several ternary eutectic compositions for designing TE alloy with improved properties.

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Section: Liquid Solutionmentioning

confidence: 99%

“…The optimized result of the Ga-Te binary system by the authors' recent study [29] was directly adopted in the present study. The optimized phase diagram and the integral enthalpy of mixing of liquid solution were shown in Figure 6a,b, respectively.…”

Section: Ga-te Binary Systemmentioning

confidence: 99%