Distribution of sulfate‐reducing bacteria in the crevice and its effect on the initial corrosion behavior of 2205 stainless steel in artificial seawater

Abstract

In the present study, the distribution and vitality of the sulfate‐reducing bacteria (SRB) inside the crevice were characterized by scanning electron microscopy and confocal laser scanning microscopy. Potentiodynamic polarization curve tests and electrochemical impedance spectroscopy were used to evaluate the corrosion resistance. Furthermore, a starvation experiment was conducted by controlling nutrients to investigate the effects of the crevices on the transportation of nutrients and the vitality of the SRB. The results demonstrate that it was more difficult for the SRB to enter the crevice, resulting in an incomplete biofilm formed on the surface. In addition, the insufficient supply of nutrients was also the reason for the low vitality of the SRB inside the crevice. Based on these results, it was inferred that the incomplete biofilm inside the crevice acted as a micro‐galvanic, thus making the corrosion rate of 2205 stainless steel in the initial crevice corrosion much more serious than that in the open system.