Patent ID: 6361622
Filing Date: 2002-03-26
Classification: C23C

Abstract:
A composition for coating or touching up or both coating and touching up a metal surface, said composition comprising water and:(A) from about 0.5 millimoles per kilogram to about 240 millimoles per kilogram, a unit hereafter abbreviated as â€œmM/kgâ€  of a component of fluorometallate anions, each of said anions consisting of: (i) at least four fluorine atoms; and (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron, and, optionally, one or both of (iii) at least one ionizable hydrogen atom; and (iv) at least one oxygen atom; (B) from about 0.5 grams/liter to about 10 grams/liter, a unit hereafter abbreviated as g/l, of a component of phosphorus-containing inorganic oxyanions or phosphonate anions or both phosphorus-containing inorganic oxyanions and phosphonate anions calculated as the stoichiometric equivalent of H3PO4; and (C) from about 0.5 g/l to about 3.5 g/l of hexavalent chromium, (D) from about 0.10 g/l to about 2.20 g/l of trivalent chromium cations; said liquid composition comprising not more than 0.06% of dispersed silica and silicates.