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Alfred Larsson. Portrait.

Alfred Larsson

Postdoctoral fellow

Alfred Larsson. Portrait.

Understanding passive film degradation and its effect on hydrogen embrittlement of super duplex stainless steel – Synchrotron X-ray and electrochemical measurements combined with CalPhaD and ab-initio computational studies

Author

  • Cem Örnek
  • Fan Zhang
  • Alfred Larsson
  • Mubashir Mansoor
  • Gary S. Harlow
  • Robin Kroll
  • Francesco Carlà
  • Hadeel Hussain
  • Dirk L. Engelberg
  • Bora Derin
  • Jinshan Pan
Show all

Summary, in English

The passive film stability on stainless steel can be affected by hydrogen absorption and lead to microstructure embrittlement. This work shows that the absorption of hydrogen results in surface degradation due to oxide reduction and ionic defect generation within the passive film, which decomposes and eventually vanishes. The passive film provides a barrier to entering hydrogen, but when hydrogen is formed, atomic hydrogen infuses into the lattices of the austenite and ferrite phases, causing strain evolution, as shown by synchrotron x-ray diffraction data. The vacancy concentration and hence the strains increase with increasing electrochemical cathodic polarization. Under cathodic polarization, the surface oxides are thermodynamically unstable, but the complete reduction is kinetically restrained. As a result, surface oxides remain present under excessive cathodic polarization, contesting the classical assumption that oxides are easily removed. Density-functional theory calculations have shown that the degradation of the passive film is a reduction sequence of iron and chromium oxide, which causes thinning and change of the semiconductor properties of the passive film from n-type to p-type. As a result, the surface loses its passivity after long cathodic polarization and becomes only a weak barrier to hydrogen absorption and hence hydrogen embrittlement.

Department/s

  • LU Profile Area: Light and Materials
  • LTH Profile Area: Nanoscience and Semiconductor Technology
  • Synchrotron Radiation Research
  • NanoLund: Centre for Nanoscience

Publishing year

2023

Language

English

Publication/Series

Applied Surface Science

Volume

628

Document type

Journal article

Publisher

Elsevier

Topic

  • Condensed Matter Physics (including Material Physics, Nano Physics)

Keywords

  • Ab-initio density-functional theory
  • Cathodic polarization
  • FactSage thermodynamics
  • Hydrogen embrittlement
  • Passive film
  • Super duplex stainless steel

Status

Published

ISBN/ISSN/Other

  • ISSN: 0169-4332