Corrosion action of sulfate-reducing bacteria on two stainless steels

The corrosion behaviors of 1Cr18Ni9Ti and Cr17Ni2 in the synergistic action of sulfate-reducing bacteria (SRB) and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential (E_oc) and pitting potential (E_b) of the electrodes were measured at the culture times of 0-10 days in non-immersion electrode way and immersion electrode way. It was found that E_oc for the non-immersion electrode way was the biggest on the fourth day while E_oc for the immersion electrode way was the biggest on the sixth day. E_b for the former decreased with the growth time. E_b for later shifted negatively at first, then positively, finally negatively. It was demonstrated that the corrosion resistance of 1Cr18Ni9Ti was much better than that of Cr17Ni2. The biofilm observed through the biology microscope was neither integrity nor compact. The serious pitting corrosion occurred on the electrode surface under the comprehensive action of electrochemically accelerated corrosion and SRB was observed by SEM.