The purpose of this paper is to present a brief review of how microbial fouling films affect the corrosion behavior of passive metals and alloys in fresh, brackish and sea waters. It has often been reported that microbial films change the open circuit corrosion potential (OCP) of passive metals immersed in natural waters (Mollica and Travis, 1976; Johnsen and Bardal, 1985, 1986; Scotto, et al., 1985; Dexter and Gao, 1988; Gallagher, et al., 1988; Scotto, 1989). The change has usually been in the noble (electropositive) direction, and it has been called, “ennoblement.” The significance of this effect lies in it’s influence on localized corrosion initiation and propagation. In chloride bearing waters, the initiation of pitting and crevice corrosion is statistical, with the probability of initiation increasing directly with chloride ion activity and OCP. Thus, at a given chloride level, the probability of localized corrosion initiation is increased by anything (such as a biofilm and its metabolic products) that causes the OCP to shift in the noble direction.
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- Biofouling Effects on Corrosion of Stainless Alloys in Seawater
S. C. Dexter
- Springer US
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