Electrolytic conduction of a solid insulator at high fields The formation of the anodic oxide film on aluminium

The mechanism of the electrolytic oxide coating process of aluminium is described in terms of a current of Al3+-ions penetrating into a preformed lattice of oxygen ions. This picture explains the peculiar structure of γ′Al2O3 (averaged structure of the cations) and is in rather good agreement with considerations on the basis of lattice theory concerning electrolytic conductivity of crystals at high fields.