The aluminum alloy material null which possesses the surface which is superior in phosphoric acid spelter treatment

摘要

PURPOSE:To obtain an Al alloy material with a surface having superior treatability with zinc phosphate, superior filiform corrosion resistance and adhesion of a coating film at a low cost by codepositing a specified amt. of metallic Zn and a metal oxide on the surface of an Al alloy. CONSTITUTION:Metallic Zn and a metal oxide are codeposited on the surface of an Al alloy by 0.1-1g/m2. The oxide or hydroxide of Al, Mg or Zn is preferably used as the metal oxide. The pref. Zn content of the resulting film is 95-50wt.%. The codeposition can be carried out by substitution plating. The formed codeposit acts as the anode in a zinc phosphate bath and accelerates the deposition of zinc phosphate. An Al alloy material with a surface having superior treatability with zinc phosphate can be obtd.