Biocorrosion of AISI 304 stainless steel by desulfo vibrio desulfuricans in seawater

Abstract

The corrosion behavior of AISI 304 stainless steel (SS304) in a batch system of enriched artificial seawater (EASW) in the presence of a sulfate-reducing bacteria (SRB) species (Desulfovibrio desulfuricans ATCC 27774) was investigated using analytical techniques including electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). EIS analysis showed that the polarization resistance of SS304 decreased after immersion in EASW in the presence of the SRB for 14 days compared to the control sample (in the absence of SRB). The corrosion processes were simulated using equivalent circuit models, which provided electrochemical information on the liquid/surface interface for both abiotic and biotic systems. Using AFM, pits and cracks were observed on the stainless steel surface in the presence of SRB, and a thick biofilm produced by SRB was evident in SEM micrographs, which corroborated the EIS results for the explanation of the biocorrosion mechanism. XPS analysis showed changes in the chemical states at the near-surface environment and on the surface of stainless steel. © 2008 American Chemical Society.