The coating structure having a corrosion resistance of the invention
contains a formation film formed on the surface of an aluminum alloy
material. The formation film is subjected to a zirconium phosphate
treatment. Because the zirconium phosphate reacts with an oxide film on
the surface of the aluminum alloy to form a zirconium boehmite layer and
to increase the adhesion of the coating material, a corrosion resisting
structure is obtained without need of a sealing treatment while
restraining the increase of the product cost. Also, a primer layer is
formed on the outer surface of the formation film and the primer layer is
composed of phosphomolybdic acid.