Material to Prevent Low Temperature Degradation of Zirconia

• US 20060046070A1
• Filed: 08/27/2004
• Published: 03/02/2006
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: FOUNDATION FOR SCIENTIFIC RESEARCH, ALFRED E. MANN
• Original Assignee: Foundation For Scientific Research Alfred E MANN
• Inventors: Jiang, Guangqiang
• Granted Patent: US 7,297,420 B2
• Time in Patent Office: Days
• US Class Current: 428/432
• CPC Class Codes: A61L 27/10 Ceramics or glasses
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: C04B 2111/00836 for medical or dental applications
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4529 applied from the gas phase
• CPC Class Codes: C04B 41/5031 Alumina
• CPC Class Codes: C04B 41/87 Ceramics
• CPC Class Codes: C23C 14/081 of aluminium, magnesium or beryllium
• CPC Class Codes: C23C 14/22 characterised by the process of coating

Abstract

The invention is directed to a material and a method of producing the material that is unaffected by the low-temperature degradation, humidity-enhanced phase transformation typical of yttria-stabilized zirconia, as well as of yttria-stabilized tetragonal zirconia polycrystalline ceramic (Y-TZP). Because of the high fracture toughness and high mechanical strength, this class of materials is widely used, including as implants, such as for the packaging material for small implantable neural-muscular sensors and stimulators. The destructive phase transformation rate is dramatically reduced by coating the surface of the Y-TZP component with dense alumina by a physical vapor deposition process, preferably ion beam assisted deposition.

Claims

1. A degradation resistant composition of matter for use in living tissue comprising:

an yttria-stabilized tetragonal zirconia polycrystal substrate;

a coating of alumina deposited on the substrate, said coating being deposited by ion beam assisted deposition in the presence of the substrate; and

wherein

said coating has a total porosity of less than about 1.0 percent.

2. The material of claim 1, wherein said coating has an average grain size less than about 0.5 microns.

3. The material of claim 1, wherein said coating comprises alpha-alumina, amorphous alumina, or a blend thereof.

4. The material of claim 1, wherein said coating has a thickness that is greater than about 1.6 micron and less than about 10 microns.

5. The material of claim 1, wherein said yttria-stabilized tetragonal zirconia polycrystal substrate comprises about 3 mole percent yttria.

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

13. A degradation resistant composition of matter for use in living tissue, comprising:

an yttria-stabilized tetragonal zirconia polycrystal substrate;

a moisture resistant coating of alumina deposited on the substrate;

wherein

said coating has a total porosity of less than about 1.0 percent.

14. The subject matter of claim 13, in which the coating is formed by ion beam assisted deposition.