Non-chromate conversion coatings

• US 6,638,369 B1
• Filed: 05/07/2002
• Issued: 10/28/2003
• Est. Priority Date: 05/07/2002
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Brown, Richard, Medeiros, Maria G., Tucker, Wayne C.
• Primary Examiner(s): Sheehan, John
• Assistant Examiner(s): Oltmans, Andrew L.
• Application Number:
  US10/143,176
• Publication Number:
  US 20030209292A1
• Time in Patent Office: 539 Days
• Field of Search: 148/243, 148/247, 148/273, 106/14.11, 428/472, 428/472.1
• US Class Current: 148/247
• CPC Class Codes: C23C 22/34 containing fluorides or complex fluorides

Abstract

A non-chromate conversion coating and method of applying same wherein the coating comprises a titanate, such as potassium titanate or sodium metatitanate, as a “drop-in replacement” for a chromate in an otherwise chromate-containing conversion coating.

Claims

1. A non-chromate conversion coating comprising:

sodium metatitanate, sodium fluoride, potassium ferricyanide and nitric acid.

2. A non-chromate conversion coating in accordance with claim 1 having a pH ranging from about 1.0 to about 6.0.

3. A non-chromate conversion coating in accordance with claim 1 wherein the sodium metatitanate is present in a concentration ranging from greater than 0 to about 1 M, the sodium fluoride is present in a concentration ranging from greater than 0 to about 1 M and potassium ferricyanide is present in a concentration ranging from greater than 0 to about 1 M.

11. A method of providing corrosion protection to a metal surface comprising:

applying the non-chromate conversion coating of claim 1, 4, 5, 6, 8, 9 or 10 to the metal surface.

12. A method in accordance with claim 11 further comprising washing the metal surface with a first solvent;

degreasing the metal surface;

rinsing the metal surface in deionized water or a second solvent a first time;

applying a deoxidizing solution to the metal surface;

rinsing the metal surface in deionized water a second time after applying the non-chromate conversion coating; and

air drying the metal surface.

13. A method in accordance with claim 12 wherein the first solvent is methanol or TCE;

the degreaser is a sodium hydroxide solution applied to the metal surface for about 1 minute at a temperature ranging from about 50°

C. to about 60°

C.;

the metal surface is immersed in the deionized water or the second solvent for about ten minutes at about room temperature; and

the non-chromate conversion coating has a temperature ranging from about 60°

C. to about 80°

C.

4. A non-chromate conversion coating comprising:

sodium metatitanate in a concentration ranging from greater than 0 to about 1 M;

sodium fluoride in a concentration ranging from greater than 0 to about 1 M;

potassium ferricyanide in a concentration ranging from greater than 0 to about 1 M; and

nitric acid;

wherein the coating has a pH ranging from about 1.0 to about 6.0.

5. A non-chromate conversion coating according to claim 4 excluding organic additives, structural component additives and/or chelating agents.

6. A non-chromate conversion coating comprising:

potassium titanate, sodium fluoride and nitric acid.

7. A non-chromate conversion coating in accordance with claim 6 having a pH ranging from about 1.0 to about 6.0.

8. A non-chromate conversion coating in accordance with claim 6 potassium titanate is present in an amount ranging from about 4 g/l to about 8 g/l and sodium fluoride is present in an amount ranging from about 2 g/l to about 6 g/l.

9. A non-chromate conversion coating comprising:

potassium titanate in an amount ranging from about 4 g/l to about 8 g/l;

sodium fluoride in an amount ranging from about 2 g/l to about 6 g/l; and

nitric acid;

wherein the coating has a pH ranging from about 1.0 to about 6.0.

10. A non-chromate conversion coating in accordance with claim 9 excluding organic additives, structural component additives and/or chelating agents.