Characterization of synergistic effects between erosion and corrosion in an aqueous environment using electrochemical techniques

Synergistic effects between erosion and corrosion processes on mild steel (MS) in an aqueous carbonate-bicarbonate solution were studied using electrochemical measurements from a rotating cylinder electrode (RCE) system, A rigorous basis for definition and measurement of the ''pure'' erosion rate and corrosion rate was adopted so that so-called synergism could be analyzed precisely. The total erosion-corrosion rate and the corrosion rate in the presence and absence of erosion were measured for a range of electrode potentials and rotation velocities. The corrosion rate increased significantly with the introduction of erodent because of the effect of erosion on corrosion kinetics. The total erosion-corrosion rate under active dissolution and passivation conditions essentially was the sum of the pure erosion rate and the measured (enhanced) corrosion rate, suggesting there was no significant effect of corrosion on the erosion process. However, in the active-to-passive transition regime, some synergistic effects ascribed to erosion were observed (i.e., mechanical damage was enhanced by corrosion).