| Summary: | This paper studies the corrosion behaviour of API 5L X65 carbon steel in the presence of sulfate-reducing bacteria (SRB) in a CO2 environment. The experiments carried out to examine the behaviour of corrosion were weight loss test and surface analysis. The carbon steel specimens were exposed to a control medium (without the presence bacteria consortium) and with the presence of SRB consortium for ten days under a continuous flow of CO2 gas. The corrosion products, inclusive of biofilm formations and pit penetrations, were characterised by field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), infinite focus microscopy (IFM) and x-ray diffraction (XRD). Results from the weight loss test confirmed that the specimens in the control condition (without SRB) formed uniform corrosion. In comparison, the IFM analysis proved that samples with the presence of SRB consortium promote localised corrosion. The localised corrosion event refers to a higher penetration rate value than the uniform corrosion rate in the SRB consortium. FESEM-EDS analyses proved the presence of sulfur on metal specimens exposed to SRB in a CO2 environment which supported the formation of FeS layers. Furthermore, XRD characterisation confirmed the formation of Fe3C and FeS in samples exposed to SRB. © 2022 Penerbit Universiti Kebangsaan Malaysia. All rights reserved.
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