US 4,486,241 A · Composition and process for treating steel

Abstract

Aqueous compositions and low temperature processes for treating clean steel and galvanized steel to provide a coating suitable for the application of paint thereto. The aqueous treating compositions contain: ______________________________________ Ingredient Quantity ______________________________________ zinc ion from about 0.9 to about 2.5 g/l; nickel ion from about 0.6 to about 2.0 g/l; orthophosphoric acid from about 15 to about 45 g/l; nitrate ion from about 1.0 to about 10.0 g/l. ______________________________________ The pH of the composition is adjusted to 3.0-3.5 by addition of alkali metal hydroxide. The above composition is used on clean galvanized steel. For clean ungalvanized steel, from about 0.10 to about 0.65 g/l of nitrite ion is included in the composition. Optional ingredients in the above compositions include chlorate ion, ferric ion, and a fluoride compound. The invention also relates to a metal activating composition comprising an aqueous colloidal solution of manganese ion and a titanium compound.

Claims37

Dependent claims

An aqueous composition for the treatment of clean galvanized steel consisting essentially of:

(a) from about 0.3 to about 2.5 grams/liter of divalent zinc ion;
(b) from about 1.2 to about 1.7 grams/liter of divalent nickel ion;
(c) from about 15 to about 45 grams/liter of orthophosphoric acid;
(d) from about 1.0 to about 10.0 grams/liter of nitrate ion;
and
wherein the pH of the composition is adjusted into the range of about 3.0 to about 3.5 by the addition of an alkali metal hydroxide.

3 more elements

A concentrated composition for use in formulating an aqueous coating solution for the treatment of clean ungalvanized steel or clean galvanized steel or both consisting essentially of an aqueous solution of the following ingredients:

(a) one part by weight of divalent zinc ion;
(b) from about 0.6 to about 1.1 parts by weight of divalent nickel ion;
(c) from about 6 to about 50 parts by weight of orthophosphoric acid;
and
(d) from about 0.4 to about 11.1 parts by weight of nitrate ion;
wherein the zinc ion is present in the concentrated composition in an amount greater than 2.5 grams/liter, and wherein the ingredients are present in the concentrated composition in amounts sufficient to produce a solution upon dilution with a controlled quantity of water in which the concentration of zinc ion is from about 0.9 to about 2.5 grams/liter, the concentration of nickel ion is from about 1.2 to about 1.7 grams/liter, the concentration of orthophosphoric acid is from about 15 to about 45 grams/liter, and the concentration of nitrate ion is from about 1.0 to about 10.0 grams/liter.

3 more elements

Dependencies are inferred from the claim text.

Composition and process for treating steel

Life of this patent

Composition and process for treating steel

Life of this patent

Abstract

Claims37