Electrochemical corrosion behavior of copper in marine microbial medium

The effects of salinity and microbe on the corrosion behavior of copper were investigated by using open-circuit potential of electrode, polarization curves and electrochemical impedance spectroscopy (EIS). Results show that in the sterile medium, the pure copper has more opportunity to corrode with the increase of salinity, because of the moving of the open-circuit potential towards negative direction. Scanning electron microscopy (SEM) reveals that the microbe adhesions on the copper mainly pole shape bacteria. The speed of corrosion in estuary water further increases with the microbe adhesions on the copper are higher in estuary water than in seawater. EIS results reveal that the transfer resistance and passive film resistance decrease with bacteria in estuary water and seawater. It indicate that the adhesion of marine microorganism accelerate the corrosion progress of pure copper.