Abstract
The properties of the anodic oxide films on aluminum alloys and on those which were partially clad with iron were investigated in alkaline baths containing hydrogen peroxide. The distribution of impurities in the films was examined by electron probe microanalyzer (EPMA). The results obtained were as follows: (1) Generally, the anodic oxide films of wrought aluminum alloys were thicker than those of cast alloys. An alloy containing copper (2017) forms the thickest film of all wrought aluminum alloys. (2) In anodizing an aluminum alloy containing magunesium (5052), the voltage increase was so rapid with the lapse of time that the anodizing was impossible to carry out. (3) The aluminum alloy sheet partially clad with iron (area ratio of Al/Fe: 100/1) formed an anodized film having almost the same film thickness as those of bare aluminum sheets. (4) It was considered that a brown film produced on the alloy containing copper (2017) was caused by the immigration of copper into the anodic oxide film from the alloy. Copper was found to exist near the outer surface of the anodic oxide film.
