FIELD: coating of metal articles, in particular corrosion-resistant chemical conversion coatings.
SUBSTANCE: coating of structural alloys, preferably aluminum and aluminum-based alloys is carried out by treatment in acid aqueous solution containing water soluble chromium(III) compounds, fluoride, and corrosion strength improving additive (preferably nitrotris(methylene)triphosphonic acid. Claimed method includes treatment of metal substrate with said solution free from hexavalent chromium. Article contains metal substrate, coated as described above. Article may also contain anodized aluminum substrate with sealed coat comprising trivalent chromium and phosphorus applied on anodized coat.
EFFECT: trivalent chromium-based chemical conversion coating free from hexavalent chromium; effective stable coating solution.
23 cl, 8 dwg, 2 tbl, 1 ex
