The EIS analysis of electrode reactions of CO2 corrosion of N80 steel

The electrochemical impedance spectroscopy (EIS) was used to analyse the EIS characters of CO2 corrosion of N80 steel in various electrolytes. It was found that the EIS characters have three time-loops, in which at low frequency the inductive arc was related with surface activation dissolution of steel and the capacitive arc was related with formation of corrosion film. With increasing the coverage of corrosion scale, the inductive arc would reduce and capacitive arc expand. Moreover the relationship between formation of corrosion scale and electrode reactions was discussed.