Method of surface oxidizing zirconium and zirconium alloys and resulting product

• US 20060058888A1
• Filed: 09/16/2004
• Published: 03/16/2006
• Est. Priority Date: 09/16/2004
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Hunter, Gordon, Jani, Shilesh C., Pawar, Vivek
• Granted Patent: US 7,473,278 B2
• Time in Patent Office: Days
• US Class Current: 623/23.390
• CPC Class Codes: A61F 2/30 Joints
• CPC Class Codes: A61F 2002/30024 differing in coefficient of friction
• CPC Class Codes: A61F 2002/30026 differing in wear resistance
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: C22C 45/10 with molybdenum, tungsten, niobium, tantalum, titanium, or zirconium or Hf as the major constituent
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23C 8/02 Pretreatment of the material to be coated C23C8/04 takes precedence
• CPC Class Codes: C23C 8/10 Oxidising

Abstract

A coating of blue-black or black oxidized zirconium of uniform and controlled thickness on a zirconium or zirconium alloy material is accomplished through the oxidative treatment of an amorphous zirconium or zirconium alloy substrate having an altered surface roughness. An oxidized zirconium coating of uniform and controlled thickness is especially useful on orthopedic implants of zirconium or zirconium-based alloys to provide low friction, highly wear resistant surfaces on artificial joints, such as, but not limited to, hip joints, knee joints, shoulders, elbows, and spinal implants. The uniformly thick oxidized zirconium surface of controlled depth on prostheses provide a barrier against implant corrosion caused by ionization of the metal prostheses. The invention is also useful in non-articulating implant devices such as bone plates, bone screws, etc.

Claims

1. A method of producing a uniform coating of blue-black or black oxidized zirconium on a zirconium or zirconium alloy, comprising the step of oxidizing zirconium or a zirconium alloy having an amorphous structure.

2. The method of claim 1, further comprising the step of altering the surface roughness of said zirconium or zirconium alloy prior to said step of oxidizing.

3. The method of claim 2, wherein said step of altering said surface roughness comprises altering to a surface roughness (Ra) in the range of about 3 microinches to about 25 microinches.

4. The method of claim 2, wherein said step of altering said surface roughness comprises altering to a surface roughness (Ra) in the range of about 3.5 microinches to about 7 microinches.

5. The method of claim 2, wherein said step of altering said surface roughness comprises an abrasive surface preparation process comprising:

a step selected from the group consisting of grinding, buffing, mass finishing and vibratory finishing and any combination thereof.

6. The method of claim 1, wherein said step of oxidizing comprises the use of air as an oxidant.

7. The method of claim 1, wherein said step of oxidizing comprises the use of oxygen as an oxidant.

8. The method of claim 1, wherein said zirconium or zirconium alloy comprises about 0.3 percent oxygen by weight.

9. A medical implant comprising:

a first component having a bearing surface;

a second component having a counter-bearing surface adapted to cooperate with the bearing surface;

wherein at least one of said first component or said second component comprises zirconium or a zirconium alloy having an amorphous structure;

a surface layer of blue-black or black oxidized zirconium on at least a portion of said component comprising zirconium or a zirconium alloy, said surface layer of oxidized zirconium being formed by oxidation of said zirconium or zirconium alloy.

10. The medical implant of claim 9, wherein said zirconium or zirconium alloy comprises an altered surface roughness prior to said oxidation.

11. The medical implant of claim 10, wherein said altered surface roughness comprises a surface roughness (Ra) in the range of about 3 microinches to about 25 microinches.

12. The medical implant of claim 10, wherein said altered surface roughness comprises a surface roughness (Ra) in the range of about 3.5 microinches to about 7 microinches.

13. The medical implant of claim 9, wherein said medical implant is a joint prosthesis.

14. The medical implant of claim 13, wherein said first component comprises a femoral component and said second component comprises an acetabular cup component to form a hip prosthesis.

15. The medical implant of claim 13, wherein said first component comprises a femoral component which further comprises at least one condyle and said second component comprises a tibial component to form a knee prosthesis.

16. The medical implant of claim 13, wherein said joint prosthesis is selected from the group consisting of shoulder, ankle, finger, wrist, toe, or elbow prostheses.

17. The medical implant of claim 9, wherein said medical implant is a maxillofacial or temporomandibular implant.

18. The medical implant of claim 9, wherein said surface layer of oxidized zirconium is of a thickness of up to about 20 microns.

19. The medical implant of claim 9, wherein said surface layer of oxidized zirconium is of a thickness of up to about 10 microns.

20. The medical implant of claim 9, wherein said implant further comprises an irregular surface adapted to accommodate tissue ingrowth.

21. The medical implant of claim 20, wherein the irregular surface is formed of zirconium or zirconium alloy beads attached to the outer surface of the prosthesis body, wherein at least a portion of the surface of the beads is oxidized to blue-black or black oxidized zirconium.

22. The medical implant of claim 20, wherein the irregular surface is formed of zirconium or zirconium alloy wire mesh connected to the outer surface of the prosthesis body, wherein at least a portion of the surface of the mesh is oxidized to blue-black or black oxidized zirconium.

23. The medical implant of claim 20, wherein the irregular surface is a chemically etched surface.

24. The medical implant of claim 20, wherein the irregular surface is plasma spray-deposited surface.

25. The medical implant of claim 20, wherein the irregular surface is a sintered surface.

26. A medical implant comprising:

at least one component comprising;

a substrate comprising zirconium or a zirconium alloy having an amorphous structure;

a surface layer of blue-black or black oxidized zirconium on at least a portion of said substrate;

said surface layer of oxidized zirconium being formed, by oxidation of said zirconium or zirconium alloy.

27. The medical implant of claim 26, wherein said zirconium or zirconium alloy comprises an altered surface roughness prior to said oxidation.

28. The medical implant of claim 27, wherein said altered surface roughness comprises a surface roughness (Ra) in the range of about 3 microinches to about 25 microinches.

29. The medical implant of claim 27, wherein said altered surface roughness comprises a surface roughness (Ra) in the range of about 3.5 microinches to about 7 microinches.

30. The medical implant of claim 26 wherein said layer of oxidized zirconium is of a thickness of up to about 20 microns.

31. The medical implant of claim 26, wherein said layer of oxidized zirconium coating is of a thickness of up to about 10 microns.

32. The medical implant of claim 26, wherein the implant portion of the prosthesis body further comprises an irregular surface adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

33. The medical implant of claim 32, wherein the irregular surface is formed of zirconium or zirconium alloy beads attached to the outer surface of the prosthesis body, wherein at least a portion of the surface of the beads is oxidized to blue-black or black oxidized zirconium.

34. The medical implant of claim 32, wherein the irregular surface structure is formed of zirconium or zirconium alloy wire mesh connected to the outer surface of the prosthesis body, wherein at least a portion of the surface of the mesh is oxidized to blue-black or black oxidized zirconium.

35. The medical implant of claim 32, wherein the irregular surface is a chemically etched surface.

36. The medical implant of claim 32, wherein the irregular surface is plasma spray-deposited surface.

37. The medical implant of claim 32, wherein the irregular surface is a sintered surface.

38. The medical implant of claim 26, wherein said medical implant is a vertebral implant.

39. The medical implant of claim 26, wherein said medical implant is a dental implant.

40. The medical implant of claim 26, wherein said medical implant comprises bone implant hardware.

41. The medical implant of claim 26, wherein said bone implant hardware comprises a bone plate or a bone screw.