ALUMINUM ANODIC OXIDE FILM EXCELLENT IN CORROSION RESISTANCE AND FORMATION OF ANODIC OXIDE FILM

摘要

PROBLEM TO BE SOLVED: To obtain the aluminum anodic oxide film by which a coating film formed on the anodic oxide film is surely fixed in a pore, the pore is kept closed even in the subsequent stage, and excellent corrosion resistance is obtained.;SOLUTION: The pore 3 of an anodic oxide film 2 has a large-diameter part 3c larger in diameter than a surface port 3a, and the large-diameter part has the diameter of 2-10 times to that of the port 3a. The coating film is formed by using a phosphoric acid electrolyte, controlling the initial voltage to ≤20 V and then increasing the processing voltage so that the final voltage is ≥5 times to the initial processing voltage.;COPYRIGHT: (C)2000,JPO