Researches on corrosion behaviors of carbon steel/copper alloy couple under organic coating in static and flowing seawater

The corrosion behaviors of an array of carbon steel wires coupled with an array of copper alloy wires under organic coating with artificial defect in static and flowing seawater were investigated by electrochemical impedance spectroscopy (EIS) technique. The results showed that the cathodic delamination of organic coating coated on copper alloy was more serious than that coated on carbon steel in the two seawater environments. The degree of the cathodic delamination of the WBE in flowing seawater was higher compared to that in static seawater, this was mainly related to the fact that the cathodic reduction reaction was accelerated in flowing seawater. There were electrochemical inhomogeneities of carbon steel and copper alloy under organic coating during the process of galvanic corrosion. In addition, the polarity reversal of copper alloy from anodic to cathodic was attributed to an increase in the galvanic effect between the two metals, and the polarity reversal of the carbon steel from cathodic to anodic was related to the anodic dissolution reaction.