The applicability of EIS to determine the optimal polarization potential for impressed current cathodic protection

Purpose – The purpose of this paper is to investigate the application of electrochemical impedance spectroscopy (EIS) as a tool for determining the optimum protection potential (OPP) of brass in impressed current cathodic protection (ICCP) for a given environment.Design/methodology/approach – The electrochemical measurements (EIS, polarization curves) were applied to study the electrode processes of brass in fresh water at different pH values.Findings – The paper finds that the depolarizer in the electrode process of brass corrosion is different in solutions with different pH values, and has different key steps in the electrode processes. Hence, EIS is a better tool for the determination of the optimum polarization potential for brass in fresh water when the depolarizer of the cathodic half‐cell reaction in corrosion reaction is the dissolved oxygen. However, when the depolarizer in solution is changed, and especially if the reduction reaction of depolarization is not controlled by the mass transport, the...