Microbiologically influenced corrosion behavior of S32654 super austenitic stainless steel in the presence of marine Pseudomonas aeruginosa biofilm

S32654 super austenitic stainless steel (SASS) is widely used in highly corrosive environments. However, its microbiologically influenced corrosion (MIC) behavior has not been reported yet. In this study, the corrosion behavior of S32654 SASS caused by a corrosive marine bacterium Pseudomonas aeruginosa was investigated using electrochemical measurements and surface analysis techniques. It was found that P. aeruginosa biofilm accelerated the corrosion rate of S325654 SASS, which was demonstrated by a negative shift of the open circuit potential (EOCP), a decrease of polarization resistance and an increase of corrosion current density in the culture medium. The largest pit depth of the coupons exposed in the P. aeruginosa broth for 14 days was 2.83 μm, much deeper than that of the control (1.33 μm) in the abiotic culture medium. It was likely that the P. aeruginosa biofilm catalyzed the formation of CrO3, which was detrimental to the passive film, resulting in MIC pitting corrosion.