MODIFICATION METHOD FOR AND STRUCTURE OF ANODIC OXIDE FILM, AND OUTBOARD MOTOR MADE FROM ALUMINUM ALLOY

摘要

PROBLEM TO BE SOLVED: To provide a rust-prevention structure for an anodized aluminum alloy material, which has more excellent corrosion resistance. SOLUTION: The structure of an anodic oxide film 36A in figure (a), in which the film is supposed to get damage 41 as reaches an aluminum alloy material 30, with a sharp foreign substance 39 for example, comprises that non-crystalline substance 33 covers the exposed part of the aluminum alloy material 30 to form a passivated fresh film 42, as is shown in a figure (b). Then, the passivated film 42 prevents chlorine ions in saline from attacking the aluminum alloy material 30.