Corrosion behaviors of carbon steel and stainless steel in the presence of iron oxidizing bacteria acidithiobacillus ferrooxidans
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2015 by Nace International. In this study, corrosion behaviors of carbon steel UNS G10100 and stainless steel UNS S30400 in the presence of an iron-oxidizing bacterial species: Acidithiobacillus ferrooxidans, were examined. Results showed that A. ferrooxidans cells, with or without attaching to coupons, could accelerate UNS G10100 corrosion at a rate of 3-6 that of controls without A. ferrooxidans, but showed no effect on UNS S30400 corrosion. The accelerated corrosion of UNS G10100 by A. ferrooxidans cells was due to the presence of Fe3+, produced by the metabolism of A. ferrooxidans cells when utilizing Fe2+ as the energy source to fix CO2 into glucose. The fast reaction of Fe3+ with Fe0 to form Fe2+ was prevented in the systems containing UNS S30400, probably by the chromium rich passivating layer formed on UNS S30400 surface to block the accessibility to Fe0. Without Fe2+, A. ferrooxidans cells died off, eliminating their contribution in UNS S30400 corrosion.
