Zirconia-toughened alumina biocomponent having high resistance to low temperature degradation and method for preparing same

• US 20020010070A1
• Filed: 04/24/2001
• Published: 01/24/2002
• Est. Priority Date: 04/25/2000
• Status: Abandoned Application

• Current Assignee: Saint-Gobain Advanced Ceramics Corp (Compagnie de Saint-Gobain SA)
• Original Assignee: Saint-Gobain Advanced Ceramics Corp (Compagnie de Saint-Gobain SA)
• Inventors: Blaise, Laurence, Cales, Bernard, Villermaux, Franceline
• Application Number:
  US09/841,274
• Publication Number:
  US 20020010070A1
• Time in Patent Office: Days
• US Class Current: 501/105
• CPC Class Codes: A61C 13/083 Porcelain or ceramic teeth A61C13/081 takes precedence; preparations A61K6/80
• 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 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3631 with an integral complete or partial peripheral collar or bearing shoulder at its base
• 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 2310/00011 Metals or alloys
• CPC Class Codes: A61F 2310/00203 containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61K 6/17 Particle size
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/824 : comprising transition metal oxides
• CPC Class Codes: A61L 27/10 : Ceramics or glasses
• CPC Class Codes: C04B 35/119 : with zirconium oxide

Abstract

A biomedical component comprising zirconia toughened alumina (ZTA), the ZTA comprising 1-69 wt % ZrO₂, the ZrO₂ being partially stabilized with >2.1 mol % yttria or rare earth oxide, and

wherein the component has a surface in which the zirconia fraction of the ZTA has a surface monoclinic content of less than 10 vol. % (preferably no more than 8 vol. %).

Claims

1. A biomedical component comprising zirconia toughened alumina ZTA material, the ZTA material comprising 1-69 wt % ZrO₂ , the ZrO₂ being partially stabilized with at least 2.1 mol % yttria, and

wherein the component has a surface in which the zirconia fraction of the ZTA has a surface monoclinic content of less than 10%.

2. The component of claim 1 where the ZrO₂ is partially stabilized in tetragonal phase with between 2.5 and 3.5 mol % yttria.

3. The component of claim 1 or claim 2 wherein the ZTA comprises 10-50 wt % zirconia.

4. The component of claim 3 wherein the ZTA comprises 20-30 wt % zirconia.

5. The component of any one of claims 1 to 4 wherein the surface of the zirconia toughened alumina material has a surface monoclinic content of no more than 5 vol. %.

6. The component of any one of claims 1 to 5 wherein the ZTA component surface has a surface monoclinic content of no more than 40 vol. % after exposure to five cycles of 134°

C. steam at 2 bars for 20 hours.

7. The component of claim 6 wherein the surface has a surface monoclinic content of no more than 10% after exposure to five cycles of 134°

C. steam at 2 bars for 20 hours.

8. The component of claim 7 wherein the surface has a surface monoclinic content of no more than 5% after exposure to five cycles of 134°

C. steam at 2 bars for 20 hours.

9. The component of any one of claims 1 to 8 wherein the ZTA material has a density of at least 99% of theoretical density.

10. The component of any one of claims 1 to 9 wherein the component surface has a surface roughness Ra of no more than 10 nm.

11. The component of any one of claims 1 to 10 wherein the zirconia has a mean grain size of no more than 0.5 μ

m.

12. The component of any one of claims 1 to 10 wherein the component is a hip joint prosthesis head.

13. The component of any one of claims 1 to 10 wherein the component is an insert for an acetabular cup.

14. The component of any one of claims 1 to 10 wherein the component is a tibial plate.

15. The component of any one of claims 1 to 10 wherein the component is a femoral knee component.

16. The component of any one of claims 1 to 10 wherein the component is an intervertebral disc.

17. The component of any one of claims 1 to 10 wherein the component is a tooth prosthesis component.

18. A method for preparing a biocomponent comprising a zirconia toughened alumina material ceramic having a resistance to low temperature degradation comprising the following process steps:

preparing a powder comprising zirconia and alumina, with a yttria content of more than 2.1 mol. %,

sintering at the lowest temperature to insure at least 95% of theoretical density,

hot isostatic pressing the already-sintered body in order to reach full density (99% of theoretical density); and

finishing and polishing the working surface in order to reach a surface roughness Ra of less 10 nm, more preferably no more than 5 nm.

19. The method of claim 18 wherein the yttria content is between 2.9 wt. % and 3.2 wt. %.

20. The method of claim 18 or claim 19 wherein the sintering is made at a temperature comprised between 1400°

C. and 1450°

C.