Claims
- 1. A process for chemically milling a metal part comprising the steps of:preparing a milling solution containing nitric acid, hydrofluoric acid, dissolved titanium, a wetting agent, and water; said preparing step comprising providing said nitric acid and said hydrofluoric acid in a ratio of said nitric acid to said hydrofluoric acid in the range of from 1:1 to 2:1; thereafter, maintaining said milling solution at a temperature in the range of from 110 to 130° F.; and immersing said metal part into said milling solution for a time sufficient to mill a desired depth on at least one surface of said part.
- 2. A process according to claim 1, wherein said wetting agent comprises a surfactant and said milling solution preparing step comprises adding said surfactant to said milling solution in an amount that said milling solution has a surface tension of from about 30 dynes/cm2 to about 36 dynes/cm2.
- 3. A process according to claim 1, wherein the ratio of said nitric acid to hydrofluoric acid is in the range of from 1:1 to 1.5:1.
- 4. A process according to claim 1, wherein said milling solution preparing step comprises maintaining said dissolved titanium in an amount up to 2.5 oz./gal.
- 5. A process according to claim 4, wherein said milling solution preparing step comprises maintaining said dissolved titanium in an amount up to 0.5 oz./gal.
- 6. A process according to claim 4, wherein said milling solution preparing step comprises maintaining said dissolved titanium in an amount up to 1.5 oz./gal.
- 7. A process according to claim 4, wherein said milling solution preparing step comprises maintaining said dissolved titanium in an amount from 1.5 oz./gal. to 2.5 oz./gal.
- 8. A process according to claim 1, wherein said wetting agent comprises a fluorosurfactant.
- 9. A process according to claim 1, wherein said part is formed from a titanium alloy.
- 10. A process according to claim 1, further comprising adding to said solution at least one material which increases the milling rate of said solution.
- 11. A process according to claim 10, wherein said at least one material adding step comprises adding urea in an amount greater than 20 grams per liter.
- 12. A process according to claim 10, wherein said at least one material adding step comprises adding dissolved palladium in an amount greater than 10 ppm.
- 13. A process according to claim 12, wherein said at least one material adding step comprises adding said dissolved palladium in an amount in the range of from 50 ppm to 200 ppm.
- 14. A process according to claim 1, wherein said maintaining step comprises maintaining said solution at a temperature in the range of from 115° F. to 125° F.
- 15. A process for chemically milling a metal part comprising the steps of:preparing a milling solution containing nitric acid, hydrofluoric acid, dissolved titanium, a wetting agent, and water; said preparing step comprising providing said nitric acid and said hydrofluoric acid in a ratio of said nitric acid to said hydrofluoric acid in the range of from 1:1 to 2:1; said preparing step further comprising adding said surfactant in an amount such that said milling solution has a surface tension of from 30 dynes/cm2 to 36 dynes/cm2; thereafter, maintaining said milling solution at a temperature in the range of from 110 to 130° F.; and immersing said metal part into said milling solution for a time sufficient to mill a desired depth on at least one surface of said part.
U.S. GOVERNMENT RIGHTS
The Government may have rights in this invention, pursuant to Contract No. N00019-97-C-0050, awarded by the United States Navy.
US Referenced Citations (12)