In the marine environment, microbiologically influenced corrosion (MIC) is a major problematic issue, which leads to severe damage to metals and alloys. The prerequisite to mitigate this worldwide problem is to investigate the mechanisms of marine-corroding microbes. Therefore, the corrosion behavior of 316L stainless steel in the presence of marine Shewanella algae was investigated by means of electrochemical measurements and surface analysis. The results revealed that S. algae is capable of forming a dense and thick biofilm on the surfaces of 316L SS coupons after 7 days of incubation, which reached about a thickness of 40.4 μm. According to electrochemical results, the S. algae biofilm also induced the corrosion of 316L SS coupons. The accelerated corrosion of 316L SS coupons was in the form of pits, which was formed underneath the biofilms. The largest pit depth after 14 days of incubation time reached 9.8 μm, which was 6.7 times higher than the one immersed in abiotic medium (1.45 μm). This is the first study demonstrating the MIC of 316L SS due to the S. algae biofilm.
Keywords: 316L stainless steel; Shewanella algae; biofilm; microbiologically influenced corrosion (MIC); pitting corrosion.