Abstract
The amount of sulfate incorporated into the anodic oxide films formed on Al in sulfuric acid solution was estimated by ESCA. The ratio of total peak count (c/s) of S2P electron to that of Al2P electron in the Al oxide films was discussed with respect to the change of anode potential during the secondary electrolysis of the primarily oxidized films on Al. The results obtained were as follows. Sulfate was detected in the anodic oxide films formed in the sulfuric acid solution during the increase of anode potential in the early stage of electrolysis, and the binding energy of S2P electron was found to be 169.8eV. On the other hand, the amount of sulfate in the anodic oxide films during the decrease of anode potential in electrolysis was much smaller than that during the increase of anode potential.
