| 摘要 |
PROBLEM TO BE SOLVED: To form an oxide film which is free from defects and is superior in corrosion resistance, on the surface of a base metal of aluminum or an aluminum alloy, which is formed into a complicated shape and is manufactured by casting such as die casting. SOLUTION: A method for forming the oxide film on the surface of the base metal formed from aluminum or the aluminum alloy includes immersing the base metal into an alkaline solution, and subjecting the base metal to anodization treatment accompanied by spark discharge. The anodization treatment includes the steps of: treating the base metal at a first voltage of 200 V or higher for a predetermined period of time; and treating the base metal at other voltage which is lower than the first voltage, for a predetermined period of time according to the current density. COPYRIGHT: (C)2010,JPO&INPIT |
