Corrosion Behavior of 316L Stainless Steel in sulfate -reducing and iron -oxidizing bacteria solutions

Microorganisms are able to intensely change the electrochemical conditions at the metal/solution interface by biofilm formation . Microbiologically influenced corrosion is responsible for most of the internal corrosion in oil transmission pipelines and storage tanks. corrosion and electrochemical behavior of 3 16L stainless steel was investigated in the presence of aerobic iron oxidizing bacteria IOB and anaerobic sulfate -reducig bacteria SRB isolated from cooling water systems in an oil refinery using electrochemical measurement , scanning electron microscopy SEM and energy dispersive atom Xray analysis EDAX.the combination of SRB and IOB demonstrated higher corrosion rated than SRB or IOB alone . the results show the corrosion potential , pitting potential of 316L had a distinct decrease in the presence of bacteria , in comparison with those observed in the sterile medium for the same exposure time interval. micrometer -scale corrosion pits were observed on 3 16L stainless steel surface in the presence of bacteria. the synergies between the metal surface, abiotic corrosion products , chloride anion, and bacterial cells and their metabolic products increased the corrosion damage degree of the passive film and accelerated pitting propagation.

Keywords:

corrosion , 316L stainless steel , sulfate - reducing , iron - oxidizing.