Nano-crystalline, homo-metallic, protective coatings
The present invention provides orthopedic prosthesis having at least one metallic component that includes a metallic substrate on which an integrally formed nano-crystalline coating is formed. The coating and the substrate have at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 10 percent. Further, the nano-crystalline coatings includes crystalline grains with an average size in a range of about 1 to 999 nanometers, and more preferably in a range of about 10 to 200 nanometers. A transition region that exhibits a graded reduction in average grain size separates the coating from the substrate. The coating advantageously exhibits an enhanced hardness, and a high degree of resistance to corrosion and wear. In one application, the nano-crystalline coatings of the invention are utilized to form articulating surfaces of various orthopedic devices.
1. An orthopedic prosthesis for implantation in a patient comprising
at least one metallic component comprising
a metallic substrate, and
a protective coating integrally formed over said substrate, the coating and the substrate having at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 20 percent, and said protective coating having a nanocrystalline structure with average grain sizes ranging from about 1 nanometer to about 999 nanometers, and
a transition region extending from the coating to the substrate.
2. The orthopedic prosthesis of claim 1 , wherein an average atomic concentration of said common metallic constituent in the coating differs from an average atomic concentration in the substrate by less than about 10 percent.
3. The orthopedic prosthesis of claim 1 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 40 to about 75 percent.
4. The orthopedic prosthesis of claim 1 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 45 to about 65 percent.
5. The orthopedic prosthesis of claim 1 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 50 to about 60 percent.
6. The orthopedic prosthesis of claim 2 , wherein said metallic substrate further comprises chromium (Cr) having an average atomic concentration in a range of about 30 to about 65 percent.
7. The orthopedic prosthesis of claim 2 , wherein said metallic substrate further comprises chromium (Cr) having an average atomic concentration in a range of about 35 to about 55 percent.
8. The orthopedic prosthesis of claim 2 , wherein said metallic substrate further comprises chromium (Cr) having an average atomic concentration in a range of about 40 to about 50 percent.
9. The orthopedic prosthesis of claim 6 , wherein the coating further comprises chromium (Cr) having an average atomic concentration that differs from the average atomic concentration of chromium in the substrate by less than about 20 percent.
10. The orthopedic prosthesis of claim 6 , wherein the coating further comprises chromium (Cr) having an average atomic concentration that differs from the average atomic concentration of chromium in the substrate by less than about 10 percent.
11. The orthopedic prosthesis of claim 3 , wherein the metallic substrate further comprises molebdynum (Mo).
12. The orthopedic prosthesis of claim 1 , wherein at least one of the substrate or the coating comprises a non-metallic substance having an atomic concentration less than about 20 percent.
13. The orthopedic prosthesis of claim 12 , wherein said non-metallic substance is nitrogen.
14. The orthopedic prosthesis of claim 1 , wherein the metallic substrate comprises a Co 57.1 Cr 37.2 Mo 5.7 alloy and the nano-crystalline coating comprises a Co 60.5 Cr 39.5 alloy.
15. The orthopedic prosthesis of claim 1 , wherein said common metallic constituent comprises titanium.
16. The orthopedic prosthesis of claim 9 , wherein said substrate and said coating comprise a Ti-6Al-4V alloy.
17. The orthopedic prosthesis of claim 1 , wherein the protective coating has a thickness ranging from about 0.05 microns to about a few millimeters.
18. The orthopedic prosthesis of claim 1 , wherein the protective coating has a thickness ranging from about 0.05 microns to about 10 microns.
19. The orthopedic prosthesis of claim 1 , wherein the protective coating has a thickness ranging from about 0.3 microns to about 3 microns.
20. The orthopedic prosthesis of claim 1 , wherein an average grain size of the protective coating ranges from about 1 nanometer to about 500 nanometers.
21. The orthopedic prosthesis of claim 20 , wherein an average grain size of the protective coating ranges from about 10 nanometers to about 200 nanometers.
22. The orthopedic prosthesis of claim 21 , wherein an average grain size of the protective coating ranges from about 50 nanometers to about 200 nanometers.
23. The orthopedic prosthesis of claim 1 , wherein the protective coating exhibits a greater hardness than the substrate.
24. The orthopedic device of claim 23 , wherein the hardness of the protective coating is about 10% greater than that of the substrate.
25. The orthopedic prosthesis of claim 23 , wherein the hardness of the protective coating is about 30% greater than that of the substrate.
26. The orthopedic prosthesis of claim 1 , further comprising a plastic component articulating against the metallic component.
27. The orthopedic prosthesis of claim 26 , wherein the plastic component is formed of ultra-high molecular weight polyethylene.
28. The orthopedic prosthesis of claim 26 , wherein the prosthesis is an artificial hip.
29. The orthopedic prosthesis of claim 26 , wherein the prosthesis is an artificial knee.
30. The orthopedic prosthesis of claim 26 , wherein the prosthesis is an artificial shoulder.
31. An orthopedic prosthesis for implantation in a patient comprising
at least one metallic component comprising
a metallic substrate, and
a metallic protective coating integrally formed over said substrate, the coating and the substrate having at least one metallic constituent in common such that a concentration of said constituent in the coating differs from a concentration of said constituent in the substrate by less than about 20 percent, and said protective coating having a nanocrystalline structure with average grain sizes ranging from about 1 nanometers to about 999 nanometers, and
a transition region extending from the coating to the substrate.
32. The orthopedic prosthesis of claim 31 , wherein an atomic concentration of said common metallic constituent in the coating differs from a concentration of said constituent in the substrate by less than about 10 percent.
33. The orthopedic prosthesis of claim 31 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 40 to about 75 percent in said substrate.
34. The orthopedic prosthesis of claim 31 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 45 to about 65 percent in said substrate.
35. The orthopedic prosthesis of claim 31 , wherein said common metallic constituent comprises cobalt having an average atomic concentration in a range of about 50 to about 60 percent in said substrate.
36. The orthopedic prosthesis of claim 33 , wherein said substrate and said coating include another common metallic constituent.
37. The orthopedic prosthesis of claim 36 , wherein said another common metallic constituent comprises chromium having an average atomic concentration in a range of about 30 to about 65 percent in said substrate.
38. The orthopedic prosthesis of claim 36 , wherein said another common metallic constituent comprises chromium having an average atomic concentration in a range of about 35 to about 55 percent in said substrate.
39. The orthopedic prosthesis of claim 36 , wherein said another common metallic constituent comprises chromium having an average atomic concentration in a range of about 40 to about 50 percent in said substrate.
40. The orthopedic prosthesis of claim 37 , wherein said chromium constituent has an average atomic concentration in said coating that differs from an average atomic concentration of chromium in the substrate by less than about 20 percent.
41. The orthopedic prosthesis of claim 37 , wherein said chromium constituent has an average atomic concentration in said coating that differs from an average atomic concentration of chromium in the substrate by less than about 10 percent.
42. The orthopedic prosthesis of claim 31 , wherein said substrate comprises a Co 57.1 Cr 37.2 Mo 5.7 alloy and the nano-crystalline coating comprises a Co 60.5 Cr 39.5 alloy.
43. The orthopedic prosthesis of claim 31 , wherein said common metallic constituent comprises titanium.
44. The orthopedic prosthesis of claim 43 , wherein said substrate and said coating comprise a Ti-6Al-4V alloy.
45. The orthopedic prosthesis of claim 31 , wherein the protective coating has a thickness ranging from about 0.05 microns to about a few millimeters.
46. The orthopedic prosthesis of claim 31 , wherein the protective coating has a thickness ranging from about 0.05 microns to about 10 microns.
47. The orthopedic prosthesis of claim 31 , wherein the protective coating has a thickness ranging from about 0.3 microns to about 3 microns.
48. The orthopedic prosthesis of claim 31 , wherein an average grain size of the protective coating ranges from about 1 nanometer to about 500 nanometers.
49. The orthopedic prosthesis of claim 31 , wherein an average grain size of the protective coating ranges from about 10 nanometers to about 200 nanometers.
50. The orthopedic prosthesis of claim 49 , wherein an average grain size of the protective coating ranges from about 50 nanometers to about 200 nanometers.
51. The orthopedic prosthesis of claim 31 , wherein the protective coating exhibits a greater hardness than the substrate.
52. The orthopedic device of claim 51 , wherein the hardness of the protective coating is about 10% greater than that of the substrate.
53. The orthopedic prosthesis of claim 51 , wherein the hardness of the protective coating is about 30% greater than that of the substrate.
54. The orthopedic prosthesis of claim 31 , further comprising a plastic component articulating against the metallic component.
55. The orthopedic prosthesis of claim 54 , wherein the plastic component is formed of ultra-high molecular weight polyethylene.
56. The orthopedic prosthesis of claim 54 , wherein the prosthesis is an artificial hip.
57. The orthopedic prosthesis of claim 54 , wherein the prosthesis is an artificial knee.
58. The orthopedic prosthesis of claim 54 , wherein the prosthesis is an artificial shoulder.
59. The orthopedic prosthesis of claim 31 , wherein the transition region exhibits a graded reduction in average grain size from the substrate to the coating.