| 摘要 |
PROBLEM TO BE SOLVED: To provide a metallic material coated with a junction-type coating film without need for a thick coating film, with the risk of environmental pollution reduced and provided with excellent corrosion resistance by the ion transport inhibiting function and to furnish its production method. SOLUTION: This metallic material is coated with the coating film consisting of a cation exchanger of a polybasic acid compd. having >=0.01 milliequivalent/g cation exchange capacity, shown by Z1 (Ha Xc Od )n .H2 O and having >=0.1μm thickness as an outer layer and an anion exchanger having >=0.01 milliequivalent/g anion exchange capacity, with the hydrogens in the cation exchanger replaced by >=2 valence metal ion and having >=0.1μm thickness as an inner layer. In the formula, X and Z are independently the element constituting a polybasic acid or its compd., and (l), (n), (o), (a), (c) and (d) are independently zero or a positive number. Besides, an oxidizing agent can be incorporated into the anion exchanger inner layer. Consequently, the risk of environmental pollution is reduced as compared with the conventional chromating process, and a coated metal material excellent in corrosion resistance is obtained.
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