Patent ID: 8172561

Claim:
A metal part comprising: a base material made of a silicon-aluminum alloy having 1 to 25% by mass of silicon, and an anodic oxide film coated over at least a portion of a surface of the base material, wherein the anodic oxide film is formed by anodizing the base material at a current density that is provided to both the anode and a cathode and that increases from an initial current density of 0 A/dm 2 at a rate that is higher than or equal to 0.15 A/dm 2 per minute and lower than or equal to 0.35 A/dm 2 per minute, and once the current density reaches a prescribed current density of between 0.8 A/dm 2 and 1.2 A/dm 2 , the current density provided to the anode and the cathode is maintained at the prescribed current density.