CHROMIUM-FREE SURFACE TREATMENT METHOD FOR METAL, AND ALUMINUM OR ALUMINUM ALLOY

• Main Authors: KAMIMURA MASAYUKI, INOUE MINORU, SUGATA TOMOYUKI, NISHIMURA TOMOSHI
• Format: Patent
• Language: English
• Published: 06.11.2003
• Edition: 7
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

PROBLEM TO BE SOLVED: To provide an inexpensive chromium-free surface treatment method for metals, which uses a chromium-free metal surface treatment agent capable of providing the same corrosion resistance and adhesiveness to a paint film as a chromium-phosphate surface treatment agent does. SOLUTION: The chromium-free surface treatment method for metals comprises a step (A) of treating an article to be treated with a chromium-free metal surface treatment agent comprising a water-soluble zirconium compound and/or a water-soluble titanium compound (1), and an organic phosphonate compound (2), and a step (B) for treating the treated article in the above step (A) with an aqueous tannic solution (3), wherein a content of the above water-soluble zirconium compound and/or the above water-soluble titanium compound (1) is 40-1,000 ppm by mass base in zirconium and/or titanium terms, a content of the above organic phosphonate compound (2) is 20-500 ppm by mass base, the above chromium-free surface treatment agent has a pH of 1.6-4.0, and a tannin content in the above tannic solution (3) is 400-10,000 ppm by mass base. COPYRIGHT: (C)2004,JPO