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US 6,620,263 B1Granted
Zinc phosphating process and composition with reduced pollution potential
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorMichael L. Sienkowski
Life of this patent
Estimating the term…
Abstract
The phosphate concentration, and therefore the pollution potential, of conventional high quality phosphating compositions containing zinc, manganese, and, optionally, nickel or copper cations, can be reduced without loss of corrosion protective value of the phosphate coatings formed by maintaining concentrations of active ingredients within prescribed ranges. Under the most preferred conditions, the corrosion resistance of phosphated and then painted cold rolled steel and the paint adhesion to phosphated and then painted electrogalvanized steel are improved over values obtained with the now most commonly used commercial high quality low zinc phosphating processes.
Claims30
An aqueous liquid working composition for forming a phosphate conversion coating on a metal surface by spontaneous chemical reaction upon contact with said metal surface, said aqueous liquid working composition comprising water and the following components:
- (A) dissolved phosphate anions that have a concentration in the working composition within a range from about 1.5 g/l to about 4.5 g/l;
- (B) dissolved zinc cations that have a concentration in the working composition that is within a range from about 0.60 g/l to about 1.30 g/l;
- (C) dissolved manganese(II) cations that have a concentration in the working composition that is within a range from about 0.35 g/l to about 0.55 g/l;
- (D) at least one of:
- (i) dissolved nickel(II) cations that have a concentration in the working composition within a range from about 0.10 g/l to about 1.5 g/l;
- and
- (ii) dissolved copper cations that have a concentration in the working composition that is within a range from about 0.0011 g/l to about 0.025 g/l;
- (E) dissolved fluoride-containing anions that have a stoichiometric equivalent as fluoride in the working composition that is within a range from about 0.45 g/l to about 0.80 g/l;
- (F) dissolved nitrate ions that have a concentration in the working composition of from about 3.5 g/l to about 8.8 g/l.;
- and
- (G) dissolved accelerator consisting of at least one substance, at the specified concentration in the working composition, selected from the group consisting of:
- (i) about 0.3 g/l to about 4 g/l of chlorate ions;
- (ii) about 0.01 g/l to about 0.2 g/l of nitrite ions;
- (iii) about 0.05 g/l to about 2 g/l of m-nitrobenzene sulphonate ions;
- (iv) about 0.05 g/l to about 2 g/l of m-nitrobenzoate ions;
- (v) about 0.05 g/l to about 2 g/l of p-nitrophenol;
- (vi) about 0.005 g/l to about 0.15 g/l of hydrogen peroxide in free or bound form;
- (vii) about 0.1 g/l to about 10 g/l of hydroxylamine in free or bound form;
- and
- (viii) about 0.1 g/l to about 10 g/l of reducing sugar;
- wherein said aqueous liquid working composition has a Free Acid value within a range from about −0.5 points to about 1.20 points.
18 more elements
An aqueous liquid working composition for forming a phosphate conversion coating on a metal surface by spontaneous chemical reaction upon contact with said metal surface, said aqueous liquid working composition having been made by mixing with water at least the following substances:
- (A) a source of dissolved phosphate anions in an amount corresponding to a concentration of dissolved phosphate anions in the working composition within a range from about 1.5 g/l to about 4.5 g/l;
- (B) a source of dissolved zinc cations in an amount corresponding to a concentration of dissolved zinc cations in the working composition that is within a range from about 0.60 g/l to about 1.30 g/l;
- (C) a source of dissolved manganese(II) cations in an amount corresponding to a concentration of dissolved manganese(II) cations in the working composition that is within a range from about 0.35 g/l to about 0.55 g/l;
- (D) a source of at least one of:
- (i) dissolved nickel(II) cations in an amount corresponding to a concentration of dissolved nickel(II) cations in the working composition within a range from about 0.10 g/l to about 1.5 g/l;
- and
- (ii) dissolved copper cations in an amount corresponding to a concentration of dissolved copper cations in the working composition that is within a range from about 0.0011 g/l to about 0.025 g/l;
- (E) a source of dissolved fluorine-containing anions in an amount corresponding to a stoichiometric equivalent as fluoride in the working composition of dissolved fluorine-containing anions that is within a range from about 0.45 g/l to about 0.80 g/l;
- (F) a source of dissolved nitrate ions in an amount corresponding to a concentration of dissolved nitrate ions in the working composition of from about 3.5 g/l to about 8.8 g/l;
- and
- (G) a source of dissolved accelerator consisting of at least one substance, at the specified concentration of such dissolved ion in the working composition, selected from the group consisting of:
- (i) about 0.3 g/l to about 4 g/l of chlorate ions;
- (ii) about 0.01 g/l to about 0.2 g/l of nitrite ions;
- (iii) about 0.05 g/l to about 2 g/l of m-nitrobenzene sulphonate ions;
- (iv) about 0.05 g/l to about 2 g/l of m-nitrobenzoate ions;
- (v) about 0.05 g/l to about 2 g/l of p-nitrophenol;
- (vi) about 0.005 g/l to about 0.15 g/l of hydrogen peroxide in free or bound form;
- (vii) about 0.1 g/l to about 10 g/l of hydroxylamine in free or bound form;
- and
- (viii) about 0.1 g/l to about 10 g/l of reducing sugar;
- wherein said aqueous liquid working composition has a Free Acid value within a range from about −0.5 points to about 1.20 points.
18 more elements
A process of forming a phosphate conversion coating on a metal substrate by contacting said metal substrate with an aqueous liquid composition aqueous liquid working composition having been made by mixing with water at least the following substances:
- (A) a source of dissolved phosphate anions in an amount corresponding to a concentration of dissolved phosphate anions in the working composition within a range from about 1.5 g/l to about 4.5 g/l;
- (B) a source of dissolved zinc cations in an amount corresponding to a concentration of dissolved zinc cations in the working composition that is within a range from about 0.60 g/l to about 1.30 g/l;
- (C) a source of dissolved manganese(II) cations in an amount corresponding to a concentration of dissolved manganese(II) cations in the working composition that is within a range from about 0.35 g/l to about 0.55 g/l
- (D) a source of at least one of:
- (i) dissolved nickel(II) cations in an amount corresponding to a concentration of dissolved nickel(II) cations in the working composition within a range from about 0.10 g/l to about 1.5 g/l;
- and
- (ii) dissolved copper cations in an amount corresponding to a concentration of dissolved copper cations in the working composition that is within a range from about 0.0011 g/l to about 0.025 g/l;
- (E) a source of dissolved fluorine-containing anions in an amount corresponding to a stoichiometric equivalent as fluoride in the working composition of dissolved fluorine-containing anions that is within a range from about 0.45 g/l to about 0.80 g/l;
- (F) a source of dissolved nitrate ions in an amount corresponding to a concentration of dissolved nitrate ions in the working composition of from about 3.5 g/l to about 8.8 g/l;
- and
- (G) a source of dissolved accelerator consisting of at least one substance, at the specified concentration of such dissolved ion in the working composition, selected from the group consisting of:
- (i) about 0.3 g/l to about 4 g/l of chlorate ions;
- (ii) about 0.01 g/l to about 0.2 g/l of nitrite ions;
- (iii) about 0.05 g/l to about 2 g/l of m-nitrobenzene sulphonate ions;
- (iv) about 0.05 g/l to about 2 g/l of m-nitrobenzoate ions;
- (v) about 0.05 g/l to about 2 g/l of p-nitrophenol;
- (vi) about 0.005 g/l to about 0.15 g/l of hydrogen peroxide in free or bound form;
- (vii) about 0.1 g/l to about 10 g/l of hydroxylamine in free or bound form;
- and
- (viii) about 0.1 g/l to about 10 g/l of reducing sugar;
- wherein said aqueous liquid working composition has a Free Acid value within a range from about −0.5 points to about 1.20 points.
18 more elements
Dependencies are inferred from the claim text.