FIELD: chemical industry.
SUBSTANCE: invention relates to chemical conversion processing. Solution is proposed for chemical conversion treatment of a zinc or zinc alloy substrate containing 2–200 mmol/l of trivalent chromium ions, 1–300 mmol/l of zirconium ions, 5–500 mmol/l of fluoride ions and 0.5–8 g/l of water-soluble carboxylic acids or their salts, while the solution is free of cobalt ions and hexavalent chromium ions. Method of chemical conversion treatment of a zinc or zinc alloy substrate and a chemical conversion coating formed on a zinc or zinc alloy substrate are also proposed.
EFFECT: invention provides the metal surface of zinc or zinc alloy with excellent corrosion resistance.
8 cl, 12 ex, 5 tbl
