Corrosion Behavior of 1.4313 Steel in the Presence of Manganese Oxidizing Bacterium Isolated From Murat River (Turkey)

Abstract

1.4313 martensitic stainless steel (SS) is widely used material in petrochemical and hdyro- electric power industry preferably due to its corrosion resistance and high mechanical properties. It is reported by several researchers that manganese (Mn) oxides produced by MOB promote pitting and crevice corrosion through a combination of electrochemical effects caused by galvanic coupling between Mn oxide deposits and metallic surface including SS in industrial systems operated with natural waters.In this study, a MOB strain was isolated by water samples from Murat River (Turkey) where a hydro-electric power plant is located on, and then identified by 16S rRNA sequencing analysis. Then, 1.4313 SS` behavior was investigated in the presence of this bacterial strain. In the laboratory-scaled corrosion test system, 1.4313 SS coupons were exposed to the bacterial culture for 2, 8, 24, 48, 72, 96, 120, 144, 168, 240, 300, 360, 456, 624 ve 792 h along with a control system with sterile MOB medium. The test coupons were removed at each sampling time for enumeration of MOB, detection of Mn oxide amount, and weight loss measurement. Mn+2 ad pH values were also measured simultaneously.16S rRNA sequences revealed that the bacterial isolate was related to Enterobacter tabaci YIM Hb-3 strain with 98% similarity. The weight loss results indicated the 1.4313 SS was corroded microbiologically by Enterobacter tabaci YIM Hb-3 MOB strain.