Effects of Sulfate-Reducing Bacteria on the Corrosion of Q235

Abstract

Various corrosion media were prepared by dual-cells experimental setup, including fresh sterilized culture medium, culture medium with sulfate-reducing bacteria (SRB), and culture medium containing only SRB metabolites. Corrosion exposure tests of Q235 carbon steel were conducted in these media, and effects of SRB on the corrosion behavior of Q235 were studied by electrochemical methods and surface analyses. As the results, Q235 was uniformly corroded in the fresh sterilized culture medium in a mode of active dissolution; in the culture medium of SRB, Q235 was protected by the iron sulfides layer to some extent in the early stage of exposure, but severely localized corrosion subsequently occurred resulting from the localized breakdown of iron sulfides layer in presence of SRB and SRB biofilm; while in the culture medium containing only SRB metabolites, Q235 was well protected over the whole exposure period, suggesting that a uniform and stable layer of iron sulfides was formed in this medium.