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A chromate and phosphate free composition and method for forming a dried in place conversion coating for aluminum and aluminum alloys. The method entails the application of the composition to aluminum or aluminum alloys and allowing the composition to dry in place. The composition is an acidic aqueo

A chromate and phosphate free composition and method for forming a dried in place conversion coating for aluminum and aluminum alloys. The method entails the application of the composition to aluminum or aluminum alloys and allowing the composition to dry in place. The composition is an acidic aqueous solution preferably containing more than 8 grams per liter dihydro-hexafluozirconaic acid, more than 10 grams per liter polyacrylic acid and more than 0.17 grams per liter hydrofluoric acid in a ratio of 1:0.84:0.014. The solution forms a dried in place conversion coating having a weight of from 6 to 25 milligrams per square foot in treatment (contact and drying) times as short as 2 seconds.

대표청구항 ▼

An aqueous acidic solution which is effective in forming a dried in place non-chromate conversion coating on the surface of aluminum or alloys thereof, consisting essentially of: (a) from greater than 10 to about 16 grams per liter of a polymer selected from the group consisting of polyacrylic acid

An aqueous acidic solution which is effective in forming a dried in place non-chromate conversion coating on the surface of aluminum or alloys thereof, consisting essentially of: (a) from greater than 10 to about 16 grams per liter of a polymer selected from the group consisting of polyacrylic acid and homopolymers thereof; (b) from greater than 12 to about 19 grams per liter dihydro-hexafluozirconic acid; and (c) from about 0.17 to about 0.3 grams per liter hydrofluoric acid wherein the ratio of a:b:c is in the range of about 0.84 to about 0.89:1: up to about 0.02.