Stainless steels (SS) and other iron-based alloys are susceptible to pitting corrosion in the presence of sulfate-reducing bacteria (SRB) or their metabolites in chloride-containing media as found in a variety of industrial environments.1-4 In recent years, potentiodynamic sweep techniques have been used in laboratory experiments to assess the pitting corrosion of SS in the presence of diverse SRB metabolites,5,6 using different bacterial strains7 and microstructural states.8
The anodic scan of SS in sulfide and chloride mixtures presents two characteristic current peaks before the breakdown potential (Eb) is reached. According to the literature,9 the first peak is due to the formation of a ferrous sulfide film, later electro-oxidized to elemental sulfur at the potential values corresponding to the second current peak. A decrease in the resistance of SS to breakdown and pitting is confirmed by the more negative Eb values obtained in chloride plus sulfide solutions...
