Anisotropy of electrochemical porous anodic oxidation of aluminium

Electric resistance of an aluminum foil was used to monitor its temperature during anodization in the regimes providing porous alumina formation. Current densities higher than 100 mA/cm
²
were found to be accompanied by the sample heating several tens of degrees above the electrolyte temperature. Local heating of different regions in the forming porous nanostructured alumina was calculated to show considerable anisotropy of the effect.