Corrosion of artificial rock layer covered steel electrodes in a CO2 environment: The influence of permeability

Under-deposit corrosion was investigated by the design of a rock layer covered electrode to tailor the permeability of deposit layers. The electrochemical behavior and corrosion morphologies were found to be closely dependent on the permeability of electrodes and the duration of immersion. Electrochemical reactions at the steel/rock layer interface would be retarded with lowering the permeability, referring to an improvement in the rock layer resistance and the interfacial charge transfer resistance of the electrodes. With immersion for longer time, the electrode resistance reaches a plateau and then turns to decrease, reflecting the onset of localized attack beneath rock layers.