Abstract
By using a high‐speed technique described in ref. (1), anodic (aluminum dissolution) polarization data have been obtained for aluminum surfaces free from oxide films and from the normal concurrent hydrogen evolution. Similarly cathodic (hydrogen evolution) polarization data have been produced for oxide‐free aluminum surfaces on which the usual simultaneous anodic process has been suppressed. These results have been applied to the interpretation of the static "mixed" potential reported in ref. (1). It has been deduced that at the mixed potential the anodic area most probably comprises less than 0.5% and the cathodic area 99.5% of the total surface.