ORTHOPEDIC IMPLANTS WITH INCREASED HARDNESS AND INCREASED DEPTH OF HARDNESS AND METHOD OF MAKING

Abstract

A prosthesis or implant device for use in joint or bone repair, or restoration of function, with improved surface hardness and depth of hardness and a process comprising treating a biocompatible alloy such that hardness and depth of hardness is improved.

Claims

1. A process for making an orthopedic implant from cobalt chromium molybdenum alloy, comprising: exposing a surface of the implant to pulse plasma nitriding for 10 to 20 hours at approximately 600 degrees Celsius; and subsequently coating the implant with a hard material layer using Arc-PVD to form a coated implant.

2. The process of claim 1, wherein the coated implant has a surface hardness of between 550 and 1300 HV0.1.

3. The process of claim 1, wherein the coated implant has a surface hardness of 1250 HV0.1.

4. The process of claim 1, wherein the coated implant has a hardness depth of between 15 to 50 micrometers.

5. The process of claim 4, wherein the coated implant has a hardness depth of approximately 35 m.

6. The process of claim 1, wherein the surface of the implant is exposed to pulse plasma nitriding for 16 hours at approximately 600 degrees Celsius.

7. A process for making an orthopedic implant from alpha-beta titanium alloy, comprising: exposing a surface of the implant to pulse plasma nitriding for 10 to 48 hours at approximately 730 to 750 degrees Celsius; and subsequently coating the implant with a hard material layer using Arc-PVD to form a coated implant.

8. The process of claim 7, wherein the coated implant has a surface hardness of between 200 HV0.1 and 1000 HV0.05.

9. The process of claim 8, wherein the coated implant has a surface hardness of approximately 950 HV0.05.

10. The process of claim 7, wherein the coated implant has a hardness depth of between 20 and 70 micrometers.

11. The process of claim 10, wherein the coated implant has a hardness depth of approximately 40 m.

12. The process of claim 7, wherein the surface of the implant is exposed to pulse plasma nitriding for 16 hours at approximately 730 to 750 degrees Celsius.

13. The process of claim 1, wherein the coating is applied to a thickness of 4.5 m plus or minus 1.5 m.

14. The process of claim 13, wherein the coating is titanium niobium nitride.

15. The process of claim 13, wherein the coating is zirconium nitride.

16. The process of claim 7, wherein the coating is applied to a thickness of 4.5 m plus or minus 1.5 m.

17. The process of claim 16, wherein the coating is titanium niobium nitride.

18. The process of claim 16, wherein the coating is zirconium nitride.

19. The process of claim 2, wherein the coated implant has a hardness depth of between 15 to 50 micrometers.

20. The process of claim 8, wherein the coated implant has a hardness depth of between 20 and 70 micrometers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0019] A preferred embodiment of the invention employs pulse plasma nitriding followed by Arc-PVD to increase the surface hardness and depth of hardness of orthopedic implants made of titanium alloys or cobalt chromium molybdenum alloys.

[0020] In these preferred embodiments, an orthopedic implant made of CoCrMo undergoes pulse plasma nitriding for 10 to 20 hours at approximately 600 degrees Celsius. In a most preferred embodiment the implant undergoes pulse plasma nitriding for 16 hours at approximately 600 degrees Celsius, achieving a surface hardness of approximately 1250 HV0.1 and a hardness depth of 35 micrometers.

[0021] In another embodiment, an orthopedic implant made of TiAI6V4 undergoes pulse plasma nitriding for 10 to 48 hours at approximately 730 to 750 degrees Celsius. In a most preferred embodiment, an orthopedic implant made of TiAI6V4 undergoes pulse plasma nitriding for 16 hours at approximately 730 to 750 degrees Celsius achieving a surface hardness of approximately 950 HV0.05 and a hardness depth of 40 micrometers.

[0022] After pulse plasma nitriding, the Arc-PVD process is applied to the orthopedic implants, coating them with a hard material layer of titanium niobium nitride, zirconium nitride, or another substance, with a thickness of 4.5 plus or minus 1.5 micrometers.

[0023] The foregoing description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications within the scope of the invention may be apparent to those having ordinary skill in the art.

[0024] Detailed embodiments of the present prostheses and implant devices and methods are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative and that the prostheses and implant devices and methods may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the systems and methods are intended to be illustrative, and not restrictive.

[0025] Throughout this disclosure, unless the context requires otherwise, the word comprise and variations such as comprises and comprising will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0026] Throughout the specification, where compositions are described as including components or materials, it is contemplated that the compositions can also consist essentially of, or consist of, any combination of the recited components or materials, unless described otherwise. Likewise, where methods are described as including particular steps, it is contemplated that the methods can also consist essentially of, or consist of, any combination of the recited steps, unless described otherwise. The invention illustratively disclosed herein suitably may be practiced in the absence of any element or step which is not specifically disclosed herein.

[0027] The practice of a method disclosed herein, and individual steps thereof, can be performed manually and/or with the aid of or automation provided by electronic equipment. Although processes have been described with reference to particular embodiments, a person of ordinary skill in the art will readily appreciate that other ways of performing the acts associated with the methods may be used. For example, the order of various steps may be changed without departing from the scope or spirit of the method, unless described otherwise. In addition, some of the individual steps can be combined, omitted, or further subdivided into additional steps.