CHROMIUM-FREE METAL SURFACE TREATMENT AGENT, AND METAL SURFACE TREATMENT METHOD USING SAME

摘要

Disclosed is a chromium-free metal surface treatment agent which can provide a coating film having excellent adhesion properties and corrosion resistance and which is useful at the same level as that of the treatment with a chromate. Specifically disclosed is a chromium-free metal surface treatment agent for aluminum, an aluminum alloy, zinc or a zinc alloy, which is characterized by comprising an organic phosphonic acid polymer and a water-soluble complex fluoride. The organic phosphonic acid polymer is preferably a copolymer of acrylic acid and vinyl phosphonate. The water-soluble complex fluoride is preferably fluorotitanic acid.