Patent ID: 6881491

Claim:
A method for protecting a coatable surface of an aluminum alloy article, said article having a surface containing oxides and organic contaminants, comprising a. contacting at least one coatable surface of aluminum alloy article containing at least about 0.1 wt. % magnesium and interior diffused hydrogen with a caustic solution having a pH greater than 8, rinsing said coatable surface with water, contacting said coatable surface with an acid solution having a pH less than 6, and again rinsing said coatable surface with water, thereby to remove organics and oxide present on said coatable surface, such that any oxide layer remaining on the surface has a thickness of less than 100 nm; b. while the oxide layer thickness remains less than 100 nm, applying to said coatable surface a coating comprising an organic resin and a fluorine compound so that the coatable surface is covered by at least about 50,000 fluorine atoms per square nm; and c. heating the coated article to a temperature above about 400° C. to allow hydrogen degassing and to decompose said organic resin and at least a portion of said fluorine compound.