Coating compositions and method for the treatment of metal surfaces
AssigneeCoral Chemical Company
InventorsNarayan Das, Peter M. Stastny
Life of this patent
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Abstract
An aqeuous acidic composition provides improved coating for aluminum. The composition comprises from about 10 to about 150 ppm zirconium, from about 20 to about 250 ppm fluoride, from about 30 to about 125 ppm tannin, from about 15 to about 100 ppm phosphate and from about 5 to about 50 ppm zinc, said coating solution having a tannin to phosphate ratio in the range of at least about 1:1 to about 2:1 and a pH in the range of about 2.3 to about 2.95.
Claims15
A non-chromate coating solution effective in forming a coating on aluminum comprising:
- from about 10 to about 150 ppm zirconium, from about 20 to about 250 ppm fluoride, from about 30 to about 125 ppm tannin, from about 15 to about 100 ppm phosphate and from about 5 to about 50 ppm zinc, said coating solution having a tannin to phosphate ratio in the range of at least about 1:1 to about 2:1 and a pH in the range of about 2.3 to about 2.95.
A non-chromate process for forming a corrosion resistant paint receptive coating on an aluminum surface comprising contacting the aluminum surface with a treatment composition having a pH from about 2.3 to about 2.95, said treatment composition comprising from about 10 ppm to about 150 ppm zirconium, from about 20 ppm to about 250 ppm fluoride, from about 30 ppm to about 125 ppm tannin, from about 15 ppm to about 100 ppm phosphate and from about 5 ppm to about 50 ppm zinc, said composition having a tannin to phosphate ratio in the range of about 1:1 to about 2:1.
Dependencies are inferred from the claim text.