The oxide film growth proceeds for both substrates at efficiency
a little lower than 60% without being affected significantly by
the kind of substrate. After 30 ◦C the production of porous film is
very limited. The oxide films formed on the alloy after 40 min of
anodizing have a thickness higher than that of the film formed on
pure aluminum under the same anodizing conditions. However
the ratio of the thickness of the oxide film of the alloy to that of
pure aluminum decreases with increase of Tanod until 30–35 ◦C
and then it increases.