CONCERNING THE DISTRIBUTION OF THE OVERPOTENTIAL DURING ANODIC OXIDE FILM GROWTH

Data obtained for the repassivation of a number of metals (Fe, Cr, Ni, Ta, and W) by oxide film growth provide evidence for the separation of the applied overpotential into two regions: one lies across the oxide film itself and the other across either of the metal/film or film/electrolyte interface. The former controls transport through the oxide in accordance with the classical high field ion conduction equation; the latter controls the metal oxidation reaction and follows a Tafel relationship. The kinetic parameters associated with each of the processes are presented. © 1990, The Electrochemical Society, Inc. All rights reserved.