The Co-Sb-Ga System: Isoplethal Section and Thermodynamic Modeling

Wojciech Gierlotka, Sinn wen Chen*, Wei an Chen, Jui shen Chang, G. Jeffrey Snyder, Yinglu Tang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The Co-Sb-Ga ternary system is an important thermoelectric material system, and its phase equilibria are in need of further understanding. The CoSb3-GaSb isoplethal section is experimentally determined in this study. Phase equilibria of the ternary Co-Sb-Ga system are assessed, and the system’s thermodynamic models are developed. In addition to the terminal phases and liquid phase, there are six binary intermediate phases and a ternary Co3Sb2Ga4 phase. The Ga solution in the CoSb3 compound is described by a dual-site occupation (GaVF)xCo4Sb12−x/2(GaSb)x/2 model. Phase diagrams are calculated using the developed thermodynamic models, and a reaction scheme is proposed based on the calculation results. The calculated results are in good agreement with the experimentally determined phase diagrams, including the CoSb3-GaSb isoplethal section, the liquidus projection, and an isothermal section at 923 K (650 °C). The dual-site occupation (GaVF)xCo4Sb12−x/2(GaSb)x/2 model gives good descriptions of both phase equilibria and thermoelectric properties of the CoSb3 phase with Ga doping.

Original languageEnglish (US)
Pages (from-to)1488-1499
Number of pages12
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume46
Issue number4
DOIs
StatePublished - Apr 2015

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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