A fundamental study of an Fe-Cr(111) binary alloy-metal oxide(110)-water interfaces

Nishith Kumar Das, Tetsuo Shoji

Research output: Contribution to journalConference articlepeer-review

Abstract

Tight-binding quantum chemical molecular dynamics (QCMD) method was used to study Fe- Cr/Cr2O3/H2O interfaces in a boiling water reactor (BWR) environment. The system under study comprises an Fe-Cr (111) binary alloy covered with a Cr2O3 (110) surface and four water molecules. Reaction at the metal and oxygen-terminating metal oxide interface causes diffusion of oxygen ions into the metal surface and segregation of the metal ions. Concurrently, the interaction at the metal oxide-water interface causes the dissociation of water molecules. As a result, dissociated hydrogen atoms diffuse into the oxide film and are trapped at the interstitial sites. Hydrogen in the oxide film reduces its protective capabilities. Atomic charge analysis shows that oxygen at the metal-metal oxide interface prefers to bond with metallic atoms in the alloy rather than in the metal oxide. Oxygen atoms gain an average charge of -0.50e during the interaction. This electron transfer process initiates oxidation of the new alloy surface. Positively charged hydrogen atoms are repulsed from the metallic atoms generating an internal stress in the oxide film. The results of the present study confirm that degradation of the oxide film takes place from both interfaces reducing the protective qualities of the film.

Original languageEnglish
JournalNACE - International Corrosion Conference Series
Publication statusPublished - 2011 Jul 11
EventCorrosion 2011 - Houston, TX, United States
Duration: 2011 Mar 132011 Mar 17

Keywords

  • Austenitic stainless steel
  • Computational chemistry
  • Oxidation initiation
  • Oxide film degradation

ASJC Scopus subject areas

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

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