PRECOATED ALUMINUM ALLOY MATERIAL EXCELLENT IN CORROSION RESISTANCE AFTER FABRICATION

摘要

PROBLEM TO BE SOLVED: To provide an aluminum alloy material which is excellent in filiform corrosion resistance, water resistance, etc., and can dispense with the substrate treatment before coating by forming a coating film of an aluminum oxide hydrate on the surface of an aluminum alloy material and applying a lubricant to the coating film.;SOLUTION: An aluminum oxide hydrate coating film 2 which comprises a relativly coarse upper coating layer 3 consisting of a plate-like (standing- plate-like) aluminum oxide hydrate 9 and a relatively fine lower coatintg layer 4 consisting of a granular aluminum oxide hydrate 10 is formed on the surface of an aluminum alloy material 1. A coating film 5 which is not accompanied by an electrochemical reaction is formed on the aluminum oxide hydrate coating film 2 in the case of a fabricated and coated aluminum alloy material 8. This coating film 5 is composed of e.g. an intercoating 6 or a topcoating 7 formed by a method, e.g. spraying, not accompanied by an electrochemical reaction. Thus, the corrosion resistance after coating can be greatly improved.;COPYRIGHT: (C)2000,JPO