The effect of scan rate on the precision of determining corrosion current by Tafel extrapolation: A numerical study on the example of pure Cu in chloride containing medium

Abstract

Although potentiodynamic polarization is a common technique for determining corrosion current, there is no consensus on the choice of scanning parameters. This study explores a 1D mathematical model of copper under oxygen reduction in a chloride containing medium to quantify the effects of scan rate, starting overpotential, and scan direction on the features of polarization curve. All the relevant tendencies of the cathodic branch are reproduced experimentally and explained by local oxygen consumption and coverage by CuCl. The corresponding effects on the precision of determining corrosion current are discussed, revealing that the largest deviation of up to 50% is obtained for the slowest scan rate and largest starting overpotential.