Method of protectively coating metallic aluminum containing substrate

A method is disclosed for protecting aluminum and aluminum alloys by the chemical bonding of a polymerized coating to the aluminum oxide on the aluminum surface. The protective coating is graft polymerized from a solution onto the aluminum in the presence of a small amount of silver ion as an initiator. A peroxide is present during the graft polymerization to regenerate silver ions and to catalyze polymerization of monomers and prepolymers which attach to the aluminum surface. The monomers are vinyl monomers containing one or more hydroxy, carboxy, glycidyl and aziridinyl groups. The prepolymers are polyurethane resins and aliphatic, cycloaliphatic and aromatic epoxy resins. The vinyl monomers and prepolymers are cross-linked to provide a transparent, impervious protective coating on the aluminum. The coated aluminum article made by the above method is also disclosed.