The role of niobium carbides in the localised corrosion initiation of 20Cr-25Ni-Nb advanced gas-cooled reactor fuel cladding

Ronald N. Clark*, Justin Searle, Tomas L. Martin, W. S. Walters, Geraint Williams

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

5 Citations (Scopus)
29 Downloads (Pure)

Abstract

The role of niobium carbide (NbC) inclusions in directing the initiation of localised corrosion in sensitised 20Cr-25Ni-Nb stainless steel is investigated using a range of in-situ scanning techniques, allowing visualisation of corrosion behaviour over multiple length scales. Volta potential mapping shows NbC inclusions are up to 30 mV noble to the matrix, while chromium-depleted grain boundaries are up to 65 mV less noble. Corrosion initiation, shown by scanning vibrating electrode technique to comprise highly localised anode sites, is observed at grain boundaries, adjacent to the location of NbC inclusion clusters which remain unaffected by anodic dissolution of the surrounding matrix.

Original languageEnglish
Article number108365
Number of pages13
JournalCorrosion Science
Early online date30 Nov 2019
DOIs
Publication statusPublished - 1 Apr 2020

Keywords

  • A Stainless steel
  • B AFM
  • B SEM
  • C Inclusion
  • C Intergranular corrosion
  • C Pitting corrosion

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