Surface oxidation of a titanium or titanium alloy article

• US 6,210,807 B1
• Filed: 09/13/1999
• Issued: 04/03/2001
• Est. Priority Date: 07/17/1996
• Status: Expired due to Term

• Current Assignee: Ad.Surf.Eng. Limited
• Original Assignee: University of Birmingham
• Inventors: Morton, Peter Harlow, Bell, Thomas, Dong, Hanshan, Bloyce, Andrew
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Miranda, Lymarie
• Application Number:
  US09/214,874
• Time in Patent Office: 568 Days
• Field of Search: 428/472, 148/281, 427/377, 427/380
• US Class Current: 428/472
• CPC Class Codes: C23C 8/10 Oxidising

Abstract

The tribological behavior of titanium or titanium alloy article is improved by gaseous oxidation of the article at a temperature in the range of 500 to 725° C. for 0.5 to 100 hours, the temperature and time being selected such as to produce an adherent surface compound layer containing at least 50% by weight of oxides of titanium having a rutile structure and a thickness of 0.2 to 2 μm on a solid solution-strengthened diffusion zone wherein the diffusing element is oxygen and the diffusion zone has a depth of 5 to 50 μm.

Claims

1. A process for improving the tribological behavior of a titanium or titanium alloy article, comprising gaseous oxidation of the article at a temperature in the range of 580 to 620°

C. for 50 to 100 hours, the temperature and time being selected such as to produce an adherent surface compound layer containing at least 50% by weight of oxides of titanium having a rutile structure and a thickness of 0.2 to 2 μ

m on a solid solution-strengthened diffusion zone wherein the diffusing element is oxygen and the diffusion zone has a depth of 5 to 50 μ

m.

2. A process as claimed in claim 1, wherein the gaseous oxidation treatment is effected for 60 to 100 hours.

3. A process as claimed in claim 1, wherein the gaseous oxidation treatment is effected for about 75 to 100 hours at about 600°

C.

4. A process as claimed in claim 1, wherein the gaseous oxidation treatment is effected at about 600°

C. for about 75 hours.

5. A process as claimed in claim 1, wherein the gaseous oxidation treatment is effected for about 0.1 to 5 hours at about 680°

C.

6. A process as claimed in claim 1, wherein the gaseous oxidising atmosphere has an oxygen partial pressure of 0.1 to 1.

7. A process as claimed in claim 4, wherein the gaseous atmosphere is air.

8. A process as claimed in claim 1, wherein the surface compound layer has a thickness of 0.5 to 2 μ

m.

9. A process as claimed in claim 1, wherein the article is formed of a material selected from the group consisting of commercially pure grades of titanium, α

-titanium alloys, α

+β

-titanium alloys and β

-titanium alloys.

10. A process as claimed in claim 1, further including the step of shot peening the resultant treated article.