Anodic behavior of cathodically pretreated aluminum electrode

In this study, the cathodic polarization of aluminum electrodes was carried out in 0.1 M NaCl at a pH range of 3–8, using potentiodynamic method. Anodic polarization curves were recorded at several scan rates after the cathodic polarization of both the stationary and rotating electrodes at y1.8 V for a minute. Pretreatment of the electrodes at 1.8 V, the pH of the solution and the rotation rate of the electrodes were found to effect the shape of the polarization curves. The results are explained by the destruction of the passive film upon the aluminum surface with the anodic polarization. At high scan rates the passivation peak was observed after the active dissolution in a pH range of 3–6 as in the case for the other metals. The fact that the curves obtained in a weakly basic solutions with both stationary and rotating electrodes were similar is explained by the increase in the rates of chemical reactions, which cause surface passivation at the hydrogen evolution potential. q1999 Elsevier Science B.V. All rights reserved.