Method of surface oxidizing zirconium and zirconium alloys and resulting product

• US 20030220699A1
• Filed: 03/05/2003
• Published: 11/27/2003
• Est. Priority Date: 03/27/1997
• Status: Active Grant

• Current Assignee: Catherine M. Asgian, Gary L. Hines, Gordon Hunter
• Original Assignee: Catherine M. Asgian, Gary L. Hines, Gordon Hunter
• Inventors: Hunter, Gordon, Asgian, Catherine M., Hines, Gary L.
• Granted Patent: US 7,070,623 B2
• Time in Patent Office: Days
• US Class Current: 623/23.54
• CPC Class Codes: A61F 2/2803 for mandibular reconstruction temporo-mandibular joints A61F2/3099; bone plates for the jaw A61B17/8071
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/40 for shoulders
• CPC Class Codes: A61F 2/4241 for hands, e.g. fingers
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30838 Microstructures
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30909 Nets
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 : Necks
• CPC Class Codes: A61F 2002/365 : Connections of heads to necks
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2250/0026 : differing in surface structures
• CPC Class Codes: A61F 2310/00089 : Zirconium or Zr-based alloys
• CPC Class Codes: A61F 2310/00634 : Coating made of zirconium oxide or hydroxides
• CPC Class Codes: A61L 27/047 : Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06
• CPC Class Codes: A61L 27/306 : Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• 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 use of a single phase crystalline material 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 steps of altering the surface roughness of a zirconium or zirconium alloy having a single phase crystalline structure and uniform composition and subsequently oxidizing said zirconium or zirconium alloy.

2. The method of claim 1 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.

3. The method of claim 1 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.

4. The method of claim 1, 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;

or,

any combination thereof.

5. The method of claim 1, wherein the zirconium or zirconium alloy has a grain size of less than ASTM micro-grain size number 10.

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 step of altering the surface roughness of a zirconium or zirconium alloy having a single phase crystalline structure and uniform composition comprises altering the surface roughness of a zirconium or zirconium alloy having about 0.3 percent by weight of oxygen.

9. The method of claim 1 wherein said step of altering the surface roughness of a zirconium or zirconium alloy having a single phase crystalline structure and uniform composition comprises altering the surface roughness of pure alpha phase zirconium.

10. The method of claim 1, further comprising the step of producing the zirconium or zirconium alloy by a process selected from the group consisting of hot forge conversion of ingot to barstock, closed die forging, rapid solidification and powder consolidation.

11. A prosthesis for implantation in a patient, comprising:

(a) a prosthesis body formed of zirconium or zirconium alloy comprising an implant portion for inserting into the body tissue of the patient;

(b) a bearing surface comprising at least one condyle on the prosthesis body;

(c) a tibial component formed of an organic polymer or polymer based composite and adapted to cooperate with the bearing surface; and

(d) a coating of blue-black or black oxidized zirconium of uniform thickness prepared by the method of claim 1 directly on the bearing surface of the condyle portion for reducing wear of the organic polymer or polymer-based composite component.

12. The prosthesis of claim 11, wherein said thin blue-black or black oxidized zirconium coating is of a thickness of up to about 20 microns.

13. The prosthesis of claim 11, wherein said thin blue-black or black oxidized zirconium coating is of a thickness of up to about 10 microns.

14. The prosthesis of claim 11 wherein the implant portion of the prosthesis body further comprises an irregular surface structure adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

15. The prosthesis of claim 14, wherein the irregular surface structure 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.

16. The prosthesis of claim 14, 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.

17. A prosthesis for implantation in a patient, comprising:

(a) a hip prosthesis body for implantation into a femor comprising a head portion formed of zirconium or zirconium alloy;

(b) a bearing surface on the head portion of the prosthesis body;

(c) an acetabular cup having an inner surface formed of an organic polymer or a polymer-based composite, said inner surface being adapted to cooperate with the bearing surface on the head portion; and

(d) a coating of blue-black or black oxidized zirconium of uniform thickness prepared by the method of claim 1 directly on the bearing surface of the head portion for reducing wear of the acetabular cup inner surface.

18. The prosthesis of claim 17, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 20 microns.

19. The prosthesis of claim 17, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 10 microns.

20. The prosthesis of claim 17, wherein the prosthesis body further comprises an irregular surface structure adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

21. The prosthesis of claim 20 wherein the irregular surface structure is formed of zirconium or zirconium alloy beads connected 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 prosthesis of claim 20, 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.

23. A prosthesis for implantation in a patient, comprising:

(a) a prosthesis body formed of zirconium or zirconium alloy comprising an implant portion for insertion into the body tissue of the patient

(b) a bearing surface on the prosthesis body, the bearing surface being sized and shaped to engage or cooperate with a second bearing surface on another prosthesis portion, said second bearing surface being formed of an organic polymer or polymer-based composite; and

(c) a coating of blue-black or black oxidized zirconium of uniform thickness prepared by the method of claim 1, said coating having a thickness of up to about 20 microns on the bearing surface of the prosthesis body for reducing wear on the organic polymer or polymer-based second bearing surface of said another prosthesis portion.

24. The prosthesis of claim 23, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 10 microns.

25. The prosthesis of claim 23, wherein the prosthesis body is a hip joint having a head portion as a bearing surface and wherein said another prosthesis portion is an acetabular cup, said head portion being adapted to cooperate with the inner surface of the acetabular cup, said inner surface comprising an organic polymer or polymer-based composite.

26. The prosthesis of claim 23, wherein the prosthesis body is a knee joint and the bearing surface of the prosthesis body comprises at least one condyle, and wherein said another prosthesis portion comprises a tibial component formed of an organic polymer or polymer-based composite, said at least one condyle being adapted to cooperate with the tibial component.

27. The prosthesis of claim 23, wherein the prosthesis body further comprises an irregular surface structure adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

28. The prosthesis of claim 27, wherein the irregular surface structure is formed of zirconium or zirconium alloy beads connected 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.

29. The prosthesis of claim 27, 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.

30. A prosthesis for implantation in a patient, comprising:

(a) a prosthesis body formed of zirconium or zirconium alloy comprising an implant portion for inserting into the body tissue of the patient;

(b) a bearing surface on the prosthesis body;

(c) a counter-bearing surface formed of an organic polymer or polymer-based composite and adapted to cooperate with the bearing surface; and

(d) a coating of blue-black or black oxidized zirconium uniform thickness prepared by the method of claim 1 directly on the bearing surface for reducing wear of the organic polymer or polymer-based composite counter-bearing surface.

31. The prosthesis of claim 30, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 20 microns.

32. The prosthesis of claim 30, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 10 microns.

33. The prosthesis of claim 30, wherein the implant portion of the prosthesis body further comprises an irregular surface structure adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

34. The prosthesis of claim 33, wherein the irregular surface structure 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.

35. The prosthesis of claim 33, 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.

44. A non-articulating medical implant formed at least in part of zirconium or zirconium alloy material comprising a partial or complete coat of blue-black or black oxidized zirconium of uniform thickness prepared by the method of claim 1.

45. The medical implant of claim 44 selected from the group consisting of bone plates and bone screws.

36. A prosthesis for implantation in a patient, comprising:

(a) a prosthesis body having an external surface at least a portion of which is formed of zirconium or zirconium alloy, each having single phase crystalline structure and uniform composition and an altered surface roughness; and

(b) a blue-black or black oxidized zirconium coating of uniform thickness formed on said portion of the external surface by inducing an altered surface roughness on at least said portion of the external surface and subjecting said portion of the external surface of said prosthesis body to an oxidation process.

37. The prosthesis of claim 36 wherein the prosthesis body is an endoprothesis body suitable for use in a joint selected from a group consisting of knee joint, hip joint and shoulder joint.

38. The prosthesis of claim 36, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 20 microns.

39. The prosthesis of claim 36, wherein said blue-black or black oxidized zirconium coating of uniform thickness is of a thickness of up to about 10 microns.

40. The prosthesis of claim 36, wherein the prosthesis body comprises a spinal implant.

41. The prosthesis of claim 36, wherein the implant portion of the prosthesis body further comprises an irregular surface structure adapted to accommodate tissue ingrowth on a portion of the prosthesis body.

42. The prosthesis of claim 41 wherein the irregular surface structure 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.

43. The prosthesis of claim 41, 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.