Abstract
Some of factors affecting the burning phenomena of aluminum surfaces during anodic oxidation have been investigated in an oxalic acid bath under galvanostatic conditions. The burning phenomena visually occurred at the place of specimen where higher current flowed and the cooling effect by the agitation of the electrolyte was poor. The measurement of the temperature distribution of specimens' surface revealed that the burning occurs at the place of the highest temperature rise before the start of the burning. The temperature at the surface of burning gradually increased with time before the period of a large temperature increase during which the burning appeared. The onset of the large temperature increase with time preceded the burning phenomena. The bath voltage at the start of the burning was not affected by applied current densities, but it increased with decreasing concentration of oxalic acid. The thickness of the oxide film at the burning decreased with increasing applied current densities.
