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Alfred Larsson. Portrait.

Alfred Larsson

Postdoctoral fellow

Alfred Larsson. Portrait.

Passive film evolution on Ni-Cr-Mo alloys in acidic chloride solution during anodic polarization

Author

  • Josefin Eidhagen
  • Mats Hättestrand
  • Ulf Kivisäkk
  • Jan Andersson
  • Lisa Lautrup
  • Y. U.E. Xiaoqi
  • Alfred Larsson
  • Andrea Grespi
  • Mattia Scardamaglia
  • Andrey Shavorskiy
  • Edvin Lundgren
  • P. A.N. Jinshan
Show all

Summary, in English

Passivity arises from spontaneous formation of a thin protective passive film (oxide/hydroxide layer) on the metal surface, and the stability of passive film is of great importance for corrosion resistance. This study investigates the formation, stability, and transpassive dissolution of passive films on two Ni-based alloys, Alloy 625 and Alloy 59, in acidified NaCl solution, by combining in situ electrochemical synchrotron ambient pressure X-ray photoelectron spectroscopy (AP-XPS) with ex situ glow discharge optical emission spectroscopy (GD-OES) and electrochemical testing, as well as TEM and chemical analyses of the electrolyte. The use of these techniques enables a detailed analysis of chemical states of alloying elements and their distribution within passive films. AP-XPS results reveal a Cr-rich oxide in the thin passive film, which also contains Mo- and Nb-oxides enriched in the near-surface region, and a Cr-hydroxide layer on top of the surface. At increased polarization potentials, low valence Mo- and Nb-components are further oxidized to higher valence components. GD-OES results show that, in the transpassive potential region, the oxide film can grow to several tens of nm thick, while the two Ni-base alloys exhibit quite different behavior. For Alloy 625, Cr is depleted, Ni is almost not present, while Mo and Nb are dominant in the thick transpassive oxide film. In contrast, for Alloy 59 (Nb-free alloy), Cr and Mo remain enriched in the near-surface region and near the base metal, and Ni is present but below 10% in the thick transpassive oxide film. Nb in Alloy 625 forms a stable oxide and inhibits transpassive dissolution, thus contributing to corrosion resistance. By elucidating the fundamental mechanisms governing passivity breakdown, this study provides critical insights for the development of advanced Ni-based materials with enhanced corrosion resistance in aggressive environments.

Department/s

  • Lund Laser Centre, LLC
  • LTH Profile Area: Photon Science and Technology
  • LU Profile Area: Light and Materials
  • LTH Profile Area: Nanoscience and Semiconductor Technology
  • Synchrotron Radiation Research
  • NanoLund: Centre for Nanoscience
  • MAX IV Laboratory
  • MAX IV, Science division

Publishing year

2026-03

Language

English

Pages

14-25

Publication/Series

Corrosion Communications

Volume

21

Document type

Journal article

Publisher

Elsevier

Topic

  • Materials Chemistry

Keywords

  • AP-XPS
  • GD-OES
  • Ni-base alloy
  • Oxide growth
  • Passive film
  • Transpassive breakdown

Status

Published

ISBN/ISSN/Other

  • ISSN: 2667-2669