Cold gas dynamic spraying of high strength copper

1. A process for forming a combustion chamber liner comprising the steps of:

providing a mandrel formed from an aluminum containing material having a net shape of a combustion chamber liner;

depositing a powdered metal material onto said mandrel without melting said powdered metal mandrel;

said depositing step comprising depositing at least one layer of a copper alloy containing chromium and niobium using a deposition technique which does not melt said copper alloy and which causes copper alloy particles to plastically deform and bond to a surface of the mandrel and thereby creating a deposited article having the shape of said combustion chamber liner on said mandrel and having a uniform distribution of Cr 2 Nb particles in a copper matrix with fine Cr 2 Nb particles being located at copper grain boundaries; and

removing said material forming said mandrel to leave a free standing monolithic combustion chamber liner formed from said copper alloy.

2. A process according to claim 1 , wherein said particles are accelerated to a speed in the range of from 800 m/s to 1400 m/s.

3. A process according to claim 1 , wherein said particles are accelerated to a speed in the range of from 850 m/s to 1200 m/s.

4. A process according to claim 1 , wherein said removing step comprises removing said material chemically using heated sodium hydroxide.

5. A process according to claim 1 , wherein said depositing step comprises depositing a copper alloy containing from 1.0 to 10.0 wt % niobium and from 2.0 to 10.0 wt % chromium.

6. A process according to claim 1 , wherein said depositing step comprises depositing a copper alloy containing 8.0 wt % chromium and 4.0 wt % niobium.

7. A process according to claim 1 , wherein said depositing step comprises depositing a copper alloy containing 4.0 wt % chromium and 2.0 wt % niobium.

8. A process according to claim 1 , wherein said depositing step comprises providing particles of said powdered metal material having a size in the range of from a size sufficient to avoid getting swept away from the mandrel due to a bow shock layer to up to 50 microns and forming a deposit layer on at least one surface of said mandrel by passing said metal powder particles through a spray nozzle at a speed sufficient to plastically deform the metal powder particles on said at least one surface.

9. A process according to claim 8 , wherein said metal powder particles providing step comprises providing metal powder particles having a particle size in the range of from 5 microns to 25 microns.

10. A process according to claim 8 , wherein said powder providing step comprises feeding said metal powder particles to said nozzle at a feed rate of from 10 grams/min. to 100 grams/min. and at a pressure in the range of from 200 psi to 300 psi using a carrier gas selected from the group consisting of helium, nitrogen, and mixtures thereof.

11. A process according to claim 10 , wherein said feeding step comprises feeding said metal powder particles to said nozzle at a rate of from 15.0 grams/min to 50 grams/min.

12. A process according to claim 10 , wherein said carrier gas comprises helium and said feeding step comprises feeding said helium to said nozzle at a flow rate of from 0.001 SCFM to 50 SCFM.

13. A process according to claim 10 , wherein said carrier gas comprises helium and said feeding step comprises feeding said helium to said nozzle at a flow rate of from 8.0 SCFM to 15 SCFM.

14. A process according to claim 10 , wherein said carrier gas comprises nitrogen and said feeding step comprises feeding said nitrogen to said nozzle at a flow rate of from 0.001 SCFM to 30 SCFM.

15. A process according to claim 10 , wherein said carrier gas comprises nitrogen and said feeding step comprises feeding said nitrogen to said nozzle at a flow rate of from 4.0 SCFM to 10 SCFM.

16. A process according to claim 8 , wherein said forming step further comprises passing said metal powder particles through said nozzle using a main gas selected from the group consisting of helium, nitrogen, and mixtures thereof at a main gas temperature in the range of from 600° F. to 1200° F. and at a spray pressure in the range of from 200 psi to 500 psi.

17. A process according to claim 16 , wherein said passing step comprises passing said metal powder particles through said nozzle at a main gas temperature in the range of 700° F. to 800° F. a spray pressure in the range of from 250 psi to 500 psi.

18. A process according to claim 16 , wherein said main gas temperature in the range of from 725° F. to 775° F.

19. A process according to claim 16 , wherein said main gas comprises helium and wherein said passing step comprises feeding said helium to said nozzle at a rate in the range of from 0.001 SCFM to 50 SCFM.

20. A process according to claim 16 , wherein said main gas comprises helium and wherein said passing step comprises feeding said helium to said nozzle at a rate in the range of from 15 SCFM to 35 SCFM.

21. A process according to claim 16 , wherein said main gas comprises nitrogen and wherein said passing step comprises feeding said nitrogen to said nozzle at a rate in the range of from 0.001 SCFM to 30 SCFM.

22. A process according to claim 16 , wherein said main gas comprises nitrogen and wherein said passing step comprises feeding said nitrogen to said nozzle at a rate in the range of from 4.0 SCFM to 30 SCFM.

23. A process according to claim 8 , further comprising maintaining said nozzle at a distance from 10 mm to 50 mm from said at least one surface being coated.

24. A process according to claim 1 , wherein said depositing step comprises depositing said copper alloy using a cold spray deposition technique and so that no more than about 14 vol % of the alloy is formed by dispersoids of said Cr 2 Nb particles and the remainder being pure copper.

25. A process according to claim 1 , further comprising directly cold spraying an aluminum jacket on said combustion chamber line.