FORMATION OF HARD ANODICALLY OXIDIZED FILM AND ALUMINUM ALLOY FOR FORMING HARD ANODICALLY OXIDIZED FILM

摘要

PURPOSE: To form a film having uniform and high hardness in the film thickness direction, at the time of forming a hard anodically oxidized film on an aluminum alloy, by using an electrolytic bath of an ordinary temp. ;CONSTITUTION: An aluminum alloy in which intermetallic compounds or metallic grains 4 insoluble or hardly soluble in water and having 0.01 to 3μm grain size are dispersed at a density of 1×10⁴pieces/mm² or above, concretely an Al-Fe alloy contg. 0.4 to 2.0wt.% Fe or an Al-Fe-Kn allay contg. 0.4 to 2.0wt.% Fe and 0.4 to l.5% Mn or an Al-Si alloy contg. 1.0 to 6.0% Si is used as a base material 1, and the surface of this base material is subjected to anodic oxidation treatment by a sulfuric acid electrolytic bath having a bath temp. of 12 to 30°C to form a hard anodically oxidized film 2 having ≥350Hv. Moreover, the Al-Fe alloy, Al-Fe-Mn alloy or Al-Si alloy is prescribed.;COPYRIGHT: (C)1995,JPO