An electrophoretic coating processes for aluminum or aluminum alloy

摘要

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.