Dynamic dehydriding of refractory metal powders

Patent metadata

Field	Value
Publication number	US-8961867-B2
Application number	US-201313901301-A
Country	US
Kind code	B2
Filing date	May 23, 2013
Priority date	Sep 9, 2008
Publication date	Feb 24, 2015
Grant date	Feb 24, 2015

Abstract

Refractory metal powders are dehydrided in a device which includes a preheat chamber for retaining the metal powder fully heated in a hot zone to allow diffusion of hydrogen out of the powder. The powder is cooled in a cooling chamber for a residence time sufficiently short to prevent re-absorption of the hydrogen by the powder. The powder is consolidated by impact on a substrate at the exit of the cooling chamber to build a deposit in solid dense form on the substrate.

First claim

What is claimed is:

1. A method for dehydriding, the method comprising:
delivering a metal hydride powder to a converging-diverging nozzle;
heating the metal hydride powder, within the converging-diverging nozzle, thereby converting the metal hydride powder to a dehydrided metal powder within the converging-diverging nozzle,
wherein the dehydrided metal powder has a hydrogen content of 900 ppm or less;

cooling the dehydrided metal powder within the converging-diverging nozzle for a sufficiently small cooling time to prevent reabsorption of hydrogen into the metal powder;
and thereafter, depositing the dehydrided metal powder on a substrate to form a solid deposit.

2. The method of claim 1 , wherein the dehydrided metal powder is deposited on the substrate from a distance of less than approximately 10 mm.

3. The method of claim 1 , wherein heating of the metal hydride powder and the cooling of the dehydrided metal powder are performed under a positive pressure of an inert gas.

4. The method of claim 1 , wherein a hydrogen content of the metal hydride powder is greater than approximately 3900 ppm before heating.

5. The method of claim 1 , wherein the hydrogen content of the dehydrided metal powder is less than approximately 100 ppm after it is deposited.

6. The method of claim 1 , wherein the hydrogen content of the dehydrided metal powder is less than approximately 50 ppm after it is deposited.

7. The method of claim 1 , wherein the metal hydride powder comprises a refractory metal hydride powder.

8. The method of claim 1 , wherein an oxygen content of the solid deposit is less than approximately 200 ppm.

9. The method of claim 1 , wherein the dehydrided metal powder is deposited by spray deposition.

10. The method of claim 9 , wherein the dehydrided metal powder is deposited by cold spray.

11. The method of claim 1 , wherein a hydrogen content of the metal hydride powder decreases by at least two orders of magnitude during heating.

12. The method of claim 1 , wherein an oxygen content of the dehydrided metal powder does not increase during cooling.

13. The method of claim 1 , further comprising providing an inert gas within the nozzle.

14. The method of claim 1 , wherein the inert gas comprises helium.

15. The method of claim 1 , wherein the inert gas comprises argon.

16. A method for dehydriding, the method comprising:
providing nitrogen within a nozzle comprising converging and diverging portions;
heating a metal hydride powder in the nozzle to decrease a hydrogen content of the metal hydride powder, thereby forming a metal powder,
wherein the resulting metal powder has a hydrogen content of 900 ppm or less;

cooling the metal powder within the nozzle for a sufficiently small cooling time to prevent reabsorption of hydrogen into the metal powder; and
thereafter, depositing the metal powder on a substrate to form a solid deposit.

17. The method of claim 1 , wherein the metal hydride powder comprises tantalum hydride.

18. The method of claim 1 , wherein the metal hydride powder comprises niobium hydride.

19. The method of claim 1 , wherein the metal hydride powder comprises titanium hydride.

20. The method of claim 1 , wherein the metal hydride powder comprises zirconium hydride.

21. The method of claim 1 , wherein the dehydrided metal powder is cooled within the converging-diverging nozzle for less than 9 milliseconds.

22. The method of claim 1 , wherein the dehydrided metal powder is cooled within the converging-diverging nozzle for less than 0.5 milliseconds.

23. The method of claim 1 , wherein the dehydrided metal powder has the hydrogen content of 100 ppm or less.

24. The method of claim 1 , wherein the dehydrided metal powder has the hydrogen content of 50 ppm or less.

25. The method of claim 1 , wherein the dehydrided metal powder has the hydrogen content of 10 ppm or less.

26. The method of claim 1 , wherein the hydrogen content of the dehydrided metal powder is at least two orders of magnitude less than a hydrogen content of the metal hydride powder.

27. The method of claim 1 , further comprising providing nitrogen within the converging-diverging nozzle.

28. The method of claim 16 , wherein the hydrogen content of the metal powder is at least two orders of magnitude less than a hydrogen content of the metal hydride powder.

29. The method of claim 16 , wherein the metal powder has the hydrogen content of 100 ppm or less.

30. The method of claim 16 , wherein the metal powder has the hydrogen content of 16 ppm or less.

31. The method of claim 16 , wherein the metal powder has the hydrogen content of 10 ppm or less.

32. The method of claim 16 , wherein the metal powder is cooled within the nozzle for less than 9 milliseconds.

33. The method of claim 16 , wherein the metal powder is cooled within the nozzle for less than 0.5 milliseconds.

34. The method of claim 16 , wherein the metal powder is deposited by spray deposition.

35. The method of claim 34 , wherein the metal powder is deposited by cold spray.

36. The method of claim 16 , wherein the metal hydride powder comprises a refractory metal hydride powder.

37. The method of claim 16 , wherein the metal hydride powder comprises tantalum hydride.

38. The method of claim 16 , wherein the metal hydride powder comprises niobium hydride.

39. The method of claim 16 , wherein the metal hydride powder comprises titanium hydride.

40. The method of claim 16 , wherein the metal hydride powder comprises zirconium hydride.

41. The method of claim 16 , wherein the hydrogen content of the metal hydride powder is greater than approximately 3900 ppm before heating.

Assignees

• Miller Steven A
• Gaydos Mark
• Shekhter Leonid N
• Gulsoy Gokce
• Starck H C Inc

Inventors

• Miller Steven A
• Gaydos Mark
• Shekhter Leonid N
• Gulsoy Gokce

Classifications

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B22F3/003 Primary

  Apparatus, e.g. furnaces (in general F27B) · CPC title

• B22F2201/10

  Inert gases · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• B22F7/04

  with one or more layers not made from powder, e.g. made from solid metal · CPC title