Cation profiling of passive films on stainless steel formed in sulphuric and acetic acid by deconvolution of angle-resolved X-ray photoelectron spectra
2013 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 284, 700-714 p.Article in journal (Refereed) Published
An approach for determining depth gradients of metal-ion concentrations in passive films on stainlesssteel using angle-resolved X-ray photoelectron spectroscopy (ARXPS) is described. The iterative method,which is based on analyses of the oxidised metal peaks, provides increased precision and hence allowsfaster ARXPS measurements to be carried out. The method was used to determine the concentrationdepth profiles for molybdenum, iron and chromium in passive films on 316L/EN 1.4432 stainless steelsamples oxidised in 0.5 M H2SO4 and acetic acid diluted with 0.02 M Na2B4O7 · 10H2O and 1 M H2O,respectively. The molybdenum concentration in the film is pin-pointed to the oxide/metal interface andthe films also contained an iron-ion-enriched surface layer and a chromium-ion-dominated middle layer.Although films of similar composition and thickness (i.e., about 2 nm) were formed in the two electrolytes,the corrosion currents were found to be three orders of magnitude larger in the acetic acid solution.The differences in the layer composition, found for the two electrolytes as well as different oxidationconditions, can be explained based on the oxidation potentials of the metals and the dissolution rates ofthe different metal ions.
Place, publisher, year, edition, pages
2013. Vol. 284, 700-714 p.
XPS, Stainless steel, Passive films, Deconvolution, Cation distribution, Ion solubility
Research subject Materials Science
IdentifiersURN: urn:nbn:se:uu:diva-208400DOI: 10.1016/j.apsusc.2013.07.158ISI: 000324248600099OAI: oai:DiVA.org:uu-208400DiVA: diva2:652226