Impact of Microbiologically Influenced Corrosion on Protective Polymer Coatings

摘要

Mild steel panels protected with twelve different polymer coating systems have been exposed to natural seawater (NS) at Port Hueneme, CA and Key West, FL and to artificial seawater (AS) in laboratory tests. Coating performance was monitored using electrochemical impedance spectroscopy (EIS) and electrochemical noise analysis (ENA) as well as visual observations. Statistical analyses have been performed to determine the effects of coating composition on coating performance in general and attack by microorganisms in particular. After exposure to NS, the test panels have been evaluated using an environmental scanning electron microscope (ESEM) to determine spatial relationships between coating damage and bacterial colonization. Exposure results for coated panels with intentional defects demonstrated that bacteria did not colonize exposed surfaces under cathodic protection. Laboratory studies were performed for panels exposed to mixed communities of bacteria containing SRB.