Effect of Plastic Deformation on the Anodic Dissolution of Iron in Acids

Abstract

The effect of plastic deformation, introduced by cold‐rolling, on the anodic dissolution of iron was investigated using short‐time galvanostatic transients in deaerated , , and at 25°C. Cold‐rolling was found to have no effect on the anodic Tafel polarization parameters of iron. Anodic Tafel lines in have slopes of about 60 mv; the slope is reduced at higher polarizing potentials. For and the slopes were about 40 mv and 35 mv, respectively. The results indicate that the dissolution kinetics of iron is controlled by charge transfer, and any effect on the kinetics of iron dissolution, due to surface topography, is not observed. The variation of the anodic Tafel polarization parameters with the nature of the acid anion is explained by specific adsorption of anions on the iron surface in competition with OH−. The decrease in polarization of iron in solutions at higher polarizing currents indicates that adsorbed Cl− may directly participate in the dissolution process depending on the potential region of polarization.