Treatment of metal components

• US 20090236014A1
• Filed: 03/24/2008
• Published: 09/24/2009
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: University of Sheffield, Tecvac Limited (Wallwork Heat Treatment Ltd)
• Original Assignee: University of Sheffield, Tecvac Limited (Wallwork Heat Treatment Ltd)
• Inventors: Matthews, Allan, Spain, Elliott Ashley, Wilson, Junia Cristina, Leyland, Adrian, Housden, Jonathan
• Granted Patent: US 8,728,252 B2
• Time in Patent Office: Days
• US Class Current: 148/284
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: C23C 8/10 Oxidising
• CPC Class Codes: C23C 8/36 using ionised gases, e.g. ionitriding

Abstract

A process for treating a non-ferrous metal component, comprising placing the component into a process chamber at an elevated temperature, biasing the component to have a potential capable of attracting ions, introducing oxygen into the chamber at a pressure such that a glow discharge comprising oxygen ions is generated, the process chamber additionally comprising a glow discharge ionization enhancing means, and activating the glow discharge ionization enhancing means thereby increasing charged species density of the glow discharge, the oxygen ions flowing towards the component and colliding the surface thereof at least some of which diffuse into the component.

Claims

1. A process for treating a non-ferrous metal component, comprising placing the component into a process chamber at an elevated temperature, biasing the component to have a potential capable of attracting ions, introducing oxygen into the chamber at a pressure such that a glow discharge comprising oxygen ions is generated, the process chamber additionally comprising a glow discharge ionization enhancing means, and activating the glow discharge ionization enhancing means thereby increasing charged species density of the glow discharge, the oxygen ions flowing towards the component and colliding the surface thereof at least some of which diffuse into the component.

2. A process according to claim 1, wherein the glow discharge ionization enhancing means is a thermionic emission means.

3. A process according to claim 2, wherein the thermionic emission means is a filament.

4. A process according to claim 3, wherein the filament has a diameter greater than 1.0 mm.

5. A process according to claim 1 wherein the metal component is selected from titanium, aluminium, magnesium, zirconium and their alloys.

6. A process according to claim 1 wherein inert gas is introduced into the chamber, such that the partial pressure of oxygen in the chamber is less than 75%.

7. A process according to claim 1, wherein the pressure in the chamber is from 0.1 to 1.0 Pa.

8. A process according to claim 1, wherein the potential of the component is from 100 to 2000 V.

9. A process according to claim 8, wherein the potential is from 100 to 500 V.

10. A process according to claim 1, wherein the temperature of the component is from 300 to 800°

C.

11. A process according to claim 10, wherein the temperature of the component is from 400 to 700°

C.

12. A process according to claim 1, which is carried out for from 0.1 to 100 hours.

13. A process according to claim 12, which is carried out for from 0.3 to 20 hours.

14. A process according to claim 1, wherein the oxygen is varied over the duration of the process.

15. A process according to claim 14 wherein the oxygen flow intermittently ceases in between periods of oxygen flow.

16. A process according to claim 15, wherein the duty cycle ratio is from 0.25 to 0.75.

17. A process according to claim 15 or claim 16 wherein the cycle time is from 20 to 60 minutes.

18. A process according to claim 1, which is followed by a plasma heating step where the oxygen partial pressure is reduced to from 0 to 10% for a period of from 0.3 to 20 hours.

19. A process according to claim 1, which is followed by a coating process.

20. A process according to claim 19, wherein the coating process is a PVD and/or CVD coating process.

21. A metal component obtainable from a process according to claim 1.