Speaker
Dr
Bridget Ingham
(Callaghan Innovation)
Description
The corrosion of steel in aqueous saturated CO2 environments is a major industrial problem. Under certain conditions a highly protective scale of siderite (FeCO3) is formed; however, there is little information available regarding the initial nucleation processes. In recent years we have performed a number of in situ synchrotron X-ray diffraction studies using electrochemistry to accelerate the corrosion rate, exploring the effect of temperature [1], corrosion inhibitor species and concentrations [2-3], addition of Mg2+ [4] and Cr3+ [5], and steel microstructure [6] on the growth rates of crystalline FeCO3 films. These experiments all showed a significant induction period before a signal was observed. Recently we used grazing incidence small-angle X-ray scattering (GISAXS) and obtained evidence for an amorphous gel film that forms at much shorter times [7]. Our current hypothesis is that this amorphous gel then crystallises into either chukanovite (Fe2(OH)2CO3) or siderite, possibly via amorphous chukanovite as an intermediate phase.
[1] Ingham, Ko, Kear et al., Corr. Sci. 52 (2010) 3052.
[2] Ko, Laycock, Ingham & Williams, Corrosion 68 (2012) 1085.
[3] Ko, Laycock, Ingham & Williams, NACE Int. Corrosion Conf. Ser. 5 (2012) 3662.
[4] Ingham, Ko, Laycock et al., Corr. Sci. 56 (2012) 96.
[5] Ko, Ingham, Laycock & Williams, Corr. Sci. 80 (2014) 237.
[6] Ko, Ingham, Laycock & Williams, Corr. Sci. 90 (2015) 192.
[7] Ingham, Ko, Kirby, Laycock & Williams, Faraday Discuss. In press (2015). DOI: 10.1039/C4FD00218K.
| Keywords | GISAXS, corrosion, electrochemistry, film, insitu |
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Primary author
Dr
Bridget Ingham
(Callaghan Innovation)
Co-authors
Prof.
David Williams
(University of Auckland)
Dr
Monika Ko
(Quest Integrity Group)
Dr
Nick Laycock
(Qatar Shell Research & Technology Centre)
