Abstract
Anodic oxidation of a pure Al plate was carried out in an aqueous solution containing H2C2O4 and an specific additive, which was provided by Kumabou Metal Co., Ltd. MgSO4 was also added to the bath to stabilize the bath voltage on anodizing. The obtained anodic oxide film showed a Vickers hardness of more than 600. The optimum electrochemical condition to form such a super hard film was investigated on the basis of the microstructures and the mechanical properties.