In-situ synchrotron studies of the effect of nitrate on iron artificial pits in chloride solutions II. On the effect of carbon

Research output: Contribution to journalArticlepeer-review


  • Weichen Xu
  • J. Frederick W Mosselmans
  • Paul D. Quinn

Colleges, School and Institutes

External organisations

  • Chinese Academy of Sciences
  • Diamond Light Source


The effect of nitrate on the iron dissolution in artificial corrosion pits in chloride-containing solutions has been studied with in-situ synchrotron X-ray diffraction and ex-situ Raman spectroscopy. A black layer containing Fe3C and carbon was found in the pit in pure 1 M HCl at 0.1 V(Ag/AgCl), but at higher voltages up to 1 V(Ag/AgCl), the black layer was not observed and Fe3C was not detected. The dissolution of Fe3C at low potentials may be inhibited by a carbon layer. In the presence of nitrate, the black layer containing Fe3C was present at all the voltages tested, and current fluctuations were observed and found to be potential-dependent, with greater fluctuations at higher voltages. After dissolution in 1 M HCl, the metal surface appeared slightly roughened with some small cavities, but the surface became crystallographically etched after dissolution in 1 M HCl and 50 mM NaNO3.


Original languageEnglish
Pages (from-to)C243-C250
JournalJournal of the Electrochemical Society
Issue number6
Publication statusPublished - Mar 2015