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AuthorIngham, Bridget
AuthorHolmes-Hewett, William
AuthorKo, Monika
AuthorKirby, Nigel M.
AuthorSk, Mobbassar Hassan
AuthorAbdullah, Aboubakr M.
AuthorLaycock, Nicholas J.
AuthorWilliams, David E.
Available date2025-07-21T04:19:02Z
Publication Date2018
Publication NameJournal of the Electrochemical Society
ResourceScopus
Identifierhttp://dx.doi.org/10.1149/2.0101813jes
ISSN1945-7111
URIhttp://hdl.handle.net/10576/66508
AbstractGrazing-incidence small-angle X-ray scattering (GISAXS) from polycrystalline steel shows features associated with the underlying microstructure, and, in the initial stages of corrosion, with the development of very small-scale surface roughness, on the nanometer height scale. A 1Cr0.25Mo pipeline steel in hot, CO2-saturated brine develops the very small-scale surface roughness significantly faster than a simple carbon steel, although the overall dissolution current density for the two steels is almost the same. We speculate that it is due to the presence of a layer comprising ‘blobs’ of amorphous FeCO3, which grow to spread over the surface and eventually cover it, because it is significantly larger in height scale than the roughness developed during the initial stages of anodic dissolution in acidified NaCl solution, where no surface film is expected. The greater roughness on the 1Cr0.25Mo steel can be interpreted as due to small pre-crystalline nuclei, that form at much lower supersaturation, and grow faster, than on mild steel. Grazing-incidence X-ray diffraction studies show at later stages the apparent preferential dissolution of smaller crystallites of iron, with spatial size scale 0.1–1 μm. This develops significantly more slowly on the 1Cr0.25Mo than on the simple carbon steel.
SponsorThis work was supported by: New Zealand Ministry of Business, Innovation and Employment, contract CO8X1003; the New Zealand Synchrotron Group Ltd; and Qatar National Research Fund (QNRF, a member of the Qatar Foundation) through National Priority Research Program (NPRP) grant, Project No. NPRP 7-146-2-072. Although QNRF sponsored this project, it neither endorses nor rejects the findings of this research. DEW acknowledges support from the MacDiarmid Institute for Advanced Materials and Nanotechnology, NZ. Thanks also to Nick Birbilis (Monash University) for his generous advice and loan of equipment, to Erich Kisi (University of Newcastle, Australia) for the use of the VHR detector and to Bijan Kermani and Tenaris Ltd for the gift of pipeline steel. This research was undertaken on the Small Angle X-Ray Scattering and Powder Diffraction beam lines at the Australian Synchrotron, Victoria, Australia. The views expressed herein are those of the authors and are not necessarily those of the owner or operator of the Australian Synchrotron. The authors declare no competing interests.
Languageen
PublisherElectrochemical Society Inc.
SubjectGrazing-incidence small-angle X-ray scattering
Pipeline steel corrosion
Surface nanoroughness
Iron carbonate amorphous films
Crystallite dissolution kinetics
TitleSurface Layer Formation in the Earliest Stages of Corrosion of Steel in CO2-Saturated Brine at 80°C: Studied by In Situ Synchrotron X-ray Methods
TypeArticle
PaginationC842-C847
Issue Number11
Volume Number165
dc.accessType Abstract Only


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