The effect of carbon within corrosion pits of iron in chloride solutions

Weichen Xu, Trevor Rayment, Alison Davenport*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Iron artificial pits have been used in this work to investigate the effect of a carbon-based black layer that can form within a pit during iron dissolution in HCl solutions. Commercial purity iron (99.5%) and high purity iron (99.99+%) have been compared, and a black layer has been observed only in the 99.5% iron pit. It has been found that the formation of a black layer within an iron artificial pit is potential dependent: it can form at applied voltages below 0.2 V(SCE), but not at 0.6 V(SCE). The presence of a black layer can decrease the rate of mass transport inside a pit, which may help to maintain the aggressive acidic solution in an active pit. This effect has been characterised quantitatively via potentiostatic and potential step methods. In addition, the black layer has also been found to induce a small extra resistance in the solution.

Original languageEnglish
Pages (from-to)383-390
Number of pages8
JournalCorrosion Engineering Science and Technology
Issue number5
Early online date23 Mar 2017
Publication statusPublished - 4 Jul 2017


  • artificial pit
  • carbon
  • Iron
  • solid corrosion product

ASJC Scopus subject areas

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


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