Effect of Shewanella RCRI7 bacteria on the corrosion behavior of stainless steel (304SS) and carbon steel (St37)

In this article, the corrosion behavior of stainless steel (SS304) and carbon steel (St37) has been studied using immersion and potentiodynamic polarization methods in the presence of Shewanella RCRI7 bacteria. The results show that the corrosion behavior of SS304 and St37 is affected by passivation and biofilm formation. Based on the results of the immersion test, the corrosion behavior of SS304 has been much affected by passivation and the alloying elements (Cr, Ni, Mn, and Mo) so that the corrosion rate of SS304 decreased by 30% in presence of Shewanella RCRI7 bacteria at the first and fourth day of immersion. The corrosion rate in St37 has been decreased by 38% and 79% on the first and fourth day of immersion respectively, which indicates the impact of the biofilm on corrosion behavior. Potentiodynamic polarization tests show that cathodic reactions are affected by Shewanella RCRI7 bacteria and consequently the corrosion potential (Ecorr) is shifted to more negative potentials (from-360mV to -560mV for SS304 and from -610mV to -690mV for St37).