Frontiers in Materials (Jul 2021)

Oxidation Behavior of Quaternary Co-20Re-25Cr-3Si Alloy at Laboratory Air

  • Mingfeng Liu,
  • Junhuai Xiang,
  • Hua Wei,
  • Xiuhong Pan,
  • Xunhu Xu,
  • Ling Wang,
  • Shuai Zhang

DOI
https://doi.org/10.3389/fmats.2021.706489
Journal volume & issue
Vol. 8

Abstract

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The iso-thermal oxidation of the quaternary Co-20Re-25Cr-3Si alloy at 1,000–1,200 C under laboratory air for 24 h has been studied. The oxidation kinetics at 1,000–1,200 C follow parabolic law perfectly and the value of oxidation activation energy is 220.74 kJ/mol. Unlike the experimental condition of 0.1 MPa pure oxygen, under laboratory air Co-20Re-25Cr-3Si alloy presents a good oxidation resistance due to the formation of a dense and continuous layer of Cr2O3 in contact with the alloy. A 79% drop in oxygen pressure has changed the oxidation mode from catastrophic oxidation to mild oxidation. The thickness of the protective Cr2O3 layer decreases when temperature increases. Therefore, Co-20Re-25Cr-3Si alloy shows the best oxidation resistance at 1,000 C. Moreover, from another perspective, compared with Co-17Re-23Cr-3Si alloy, the addition of about 2% Cr can also improve the oxidation resistance of the alloy greatly by forming the protective Cr2O3 layer.

Keywords