Metallurgical and Materials Transactions A

, Volume 46, Issue 4, pp 1488–1499

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
Article

DOI: 10.1007/s11661-015-2763-1

Cite this article as:
Gierlotka, W., Chen, S., Chen, W. et al. Metall and Mat Trans A (2015) 46: 1488. doi:10.1007/s11661-015-2763-1

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.

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2015

Authors and Affiliations

  • Wojciech Gierlotka
    • 1
  • Sinn-wen Chen
    • 2
  • Wei-an Chen
    • 2
  • Jui-shen Chang
    • 2
  • G. Jeffrey Snyder
    • 3
    • 4
  • Yinglu Tang
    • 3
  1. 1.Department of Materials Science and EngineeringNational Dong Hwa UniversityHualienTaiwan R.O.C.
  2. 2.Department of Chemical EngineeringNational Tsing Hua UniversityHsinchuTaiwan R.O.C.
  3. 3.Materials ScienceCalifornia Institute of TechnologyPasadenaUSA
  4. 4.Department of Materials Science and EngineeringNorthwestern UniversityEvanstonUSA