Pitting corrosion behavior and mechanism of 316L stainless steel induced by marine fungal extracellular polymeric substances.

In this study, effect of extracellular polymeric substances (EPS) secreted by fungus Aspergillus terreus on the pitting corrosion of 316L stainless steels (SS) was deeply investigated by electrochemical measurements and surface analysis. Results demonstrated that adsorption of EPS can change surface wettability of 316L SS leading to a much more hydrophilic steel–water interface. EPS not only accelerates uniform corrosion but enhances pitting corrosion of 316L SS. EPS can promote the formation of metastable pitting corrosion and the subsequent growth of corrosion pits. The density of corrosion pits (>2 µm) reach (5.6 ± 0.5) × 103 pits/cm2 when EPS is 400 mg/L. • Effect of fungal EPS on the pitting corrosion behavior of 316L SS is investigated. • EPS can cause a much more hydrophilic steel–water interface. • EPS can cause a decrease of the passive film stability of 316L SS. • Anodic dissolution of Fe and cathodic reduction of oxygen are accelerated by EPS. • EPS promotes metastable pitting corrosion and the subsequent growth of corrosion pits. [ABSTRACT FROM AUTHOR]