In situ observations of early stage oxidation of Ni-Cr and Ni-Cr-Mo alloys

Xiao Xiang Yu*, Ahmet Gulec, Christopher M. Andolina, Evan J. Zeitchick, Kateryna Gusieva, Judith C. Yang, John R. Scully, John H. Perepezko, Laurence D. Marks

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Results of in situ transmission electron microscopy experiments on the early stage oxidation of Ni-Cr and Ni-Cr-Mo alloys are reported. An epitaxial rock-salt oxide with compositions outside the conventional solubility limits initiated at the surface of both alloys, progressing by a layer-by-layer mode. Kirkendall voids were found in Ni-Cr alloys near the metal/oxide interface, but were not seen in the Ni-Cr-Mo. The voids initiated in the oxide then diffused to the metal/oxide interface, driven by the misfit stresses in the oxide. A sequential oxide initiation was observed in NiCr alloys: rock-salt → spinel → corundum; however, for NiCrMo alloys, the metastable Ni2-xCrxO3 (corundum structure) phase formed shortly after the growth of the rock-salt phase. Chemical analysis shows that solute atoms were captured in the initial oxide before diffusing and transforming to more thermodynamically stable phases. The results indicate that Mo doping inhibits the formation of Kirkendall voids via an increase in the nucleation rate of corundum, which was verified by density functional theory calculations.

Original languageEnglish (US)
Pages (from-to)939-946
Number of pages8
JournalCorrosion
Volume74
Issue number9
DOIs
StatePublished - Sep 2018

Keywords

  • Density functional theory (DFT)
  • In situ environmental transmission electron microscope (ETEM)
  • Kirkendall voids
  • Molybdenum
  • Nickel-based alloys
  • Oxidation

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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    Yu, X. X., Gulec, A., Andolina, C. M., Zeitchick, E. J., Gusieva, K., Yang, J. C., Scully, J. R., Perepezko, J. H., & Marks, L. D. (2018). In situ observations of early stage oxidation of Ni-Cr and Ni-Cr-Mo alloys. Corrosion, 74(9), 939-946. https://doi.org/10.5006/2807