Abstract: In coating aluminum or aluminum alloy by contacting the aluminum or aluminum alloy with hot water or steam to form an aluminum oxide layer on its surface and thereafter electrophoretically coating the aluminum or aluminum alloy with an electrophoretic coating composition to form a resin layer, a process which is characterized in that said electrophoretic coating composition contains at least one water-soluble salt of an oxyacid selected from the group consisting of silicic acid, boric acid, phosphoric acid, vanadic acid, tungstic acid, permanganic acid, molybdic acid and stannic acid.

Abstract: A process for coating an aluminum or aluminum alloy comprising the steps of subjecting aluminum or aluminum alloy to boehmite treatment or chemical conversion treatment, conducting electrolysis using the resulting aluminum or aluminum alloy as an electrode in an aqueous solution of a water-soluble salt of at least one oxyacid, and thereafter coating electrophoretically the aluminum or aluminum alloy with an aqueous organic coating composition containing a binder resin and a water-soluble salt of at least one oxyacid to form a resin layer, said oxyacid contained in the aqueous solution and aqueous organic coating composition being at least one oxyacid selected from the group consisting of silicic acid, boric acid, phosphoric acid, molybdic acid, vanadic acid, permanganic acid, stannic acid and tungstic acid.

Abstract: A process for coating an aluminum or aluminum alloy comprising the steps of subjecting the aluminum or aluminum alloy to boehmite treatment or chemical conversion treatment, anodizing the resulting aluminum or aluminum alloy in an aqueous solution of a water-soluble salt of at least one oxyacid, and thereafter coating the aluminum or aluminum alloy with an organic coating composition to form a resin layer, said oxyacid being at least one oxyacid selected from the group consisting of silicic acid, boric acid, phosphoric acid, molybdic acid, vanadic acid, permanganic acid, stannic acid and tungstic acid.