Electrochemical and Corrosion Behavior of 316L Stainless Steel in a CO2-SO2-H2O Mixture

Although steel corrosion in a SO 2 -containing atmospheric environment has been extensively investigated, its electrochemical behavior still needs to be addressed, especially when it coexists with CO 2 in a carbon capture, utilization and storage system. In this work, electrochemical experiments with 316L stainless steel corrosion in a CO 2 -saturated solution were conducted by adding different amounts of SO 2 to a solution at 25 °C under different pH conditions. The effect of SO 2 on the cathodic reactions of 316L stainless steel corrosion in a CO 2 -saturated solution was investigated by electrochemical methods, including potentiodynamic sweep, linear polarization resistance and electrochemical impedance spectroscopy. The results showed that the presence of SO 2 increased the cathodic limiting current and corrosion rates of 316L stainless steel at the same pH. There was a “second-wave” phenomenon that appeared before the second limiting current and this new “wave” was demonstrated to be related to the direct reduction of both hydrate of SO 2 and bisulfite on the steel surface.