Effects Of Sulfate-Reducing Bacteria on Corrosion of Carbon Steel Q235 in the Crevice by EIS

The effect of sulfate reducing bacteria (SRB) on the corrosion of the carbon steel Q235 was investigated in the crevice under the simulated disbonded coating in the soil-extract solutions (SES). The results of electrochemical impedance spectroscopy (EIS) showed that the active biofilm enhanced the corrosion of the carbon steel in SES with SRB. The comparison of polarization (R-p) and charge transfer resistances (R-t) indicated that biofilm seriously influenced the reaction of the metal/solution interface and the corrosion rate of the carbon steel. The results of scanning electron microscopy (SEM) and energy disperse X-ray analysis (EDXA) found that the metabolic sulfide preferred forming on the surface of the soil grains to on the others. SRB was observed on the surface of the corrosion products.