The study on oxygen bubbles of anodic alumina based on high purity aluminum

U–t curve has been determined in anodic oxidation of high purity aluminum in two kinds of electrolytes. The formation of the barrier anodic aluminum oxide (AAO) film, the transformation from the barrier film to the porous one and the development of the porous film were analyzed in detail through the SEM micrograph. It was proposed that the porous films have developed from where they used to be seen as the phase of the formation of barrier films. The generation of O2 in metal/film interface goes with the formation of porous films, so that the AAO film, whether or not it has begun to transform from barrier type to porous type, can be judged by observing if O2 separates out or not.