Topographical profiles and mechanical property of corrosion product films on a pipeline steel in Desulfovibrio vulgaris-containing thin electrolyte layer characterised by atomic force microscopy

Abstract

ABSTRACT Internal corrosion of wet gas pipelines usually occurs in thin layers of water condensate with dissolved gases such as CO2, where a bacterial community can grow to cause microbiological corrosion. In this work, surface films generated during corrosion of an X52 pipeline steel under a CO2-containing thin electrolyte layer (TEL) in the absence and presence of Desulfovibrio vulgaris bacteria were characterised by atomic force microscopy. The film generated in the Desulfovibrio vulgaris-containing TEL, i.e. a mixture of FeS, FeCO3 and biopolymers, as compared with the film generated in the sterile TEL (i.e. FeCO3-dominant corrosion products), is topographically less compact and softer, with a reduced elastic modulus. After 7 days of immersion, the elastic modulus of the surface films generated in the sterile and D. vulgaris-containing TELs are 11.81 and 6.79 GPa, respectively.