Surface alloyed medical implant

Abstract

A medical implant is disclosed. The medical implant includes: a first biocompatible metal forming a substrate ( 210, 310, 410 ), a second biocompatible metal diffused into the first biocompatible metal to form an biocompatible alloy surface ( 220, 314, 414 ), the alloy surface further including a diffusion hardening species, wherein the diffusion hardening species may be carbon, nitrogen, oxygen, boron, or any combination thereof. A method of forming a medical implant is also disclosed. The method includes the steps of: providing a first biocompatible metal or alloy that forms a substrate ( 210, 310, 410 ), providing a second biocompatible metal or alloy, diffusing the second biocompatible metal into the first biocompatible metal to form an alloy layer ( 220, 314, 414 ), removing excess second metal material from the substrate to expose the alloy layer, and diffusion hardening the alloy layer.

1 . An implant, comprising:
 a substrate; and   a surface alloyed zone formed in the substrate, the surface alloyed zone including a surface alloyed hardened zone and a surface alloyed non-hardened zone, the surface alloyed hardened zone including at least one diffusion hardening material and the surface alloyed non-hardened zone having no diffusion hardening material.   
     
     
         2 . The implant of  claim 1 , wherein the surface alloyed zone forms at least one surface of the substrate. 
     
     
         3 . The implant of  claim 1 , wherein the surface alloyed hardened zone is formed by diffusion of the at least one diffusion hardening material into the substrate. 
     
     
         4 . The implant of  claim 3 , wherein the surface alloyed non-hardened zone is formed by preventing diffusion of the at least one diffusion hardening material into the substrate. 
     
     
         5 . The implant of  claim 4 , wherein the diffusion is performed in a vacuum of less than 10 −4  Torr and in the temperature range of approximately 600 degrees C. to approximately 1200 degrees C. 
     
     
         6 . The implant of  claim 1 , wherein the surface alloyed zone is formed in a presence of a gas, the gas being at least one of the following: carbon, oxygen, nitrogen, and any combinations thereof. 
     
     
         7 . The implant of  claim 1 , wherein the surface alloyed zone is formed in a presence of an inert gas, the inert gas being at least one of the following: argon, helium, krypton, neon, nitrogen, and any combinations thereof. 
     
     
         8 . The implant of  claim 1 , wherein the surface alloyed hardened zone is an oxide layer. 
     
     
         9 . The implant of  claim 8 , wherein the oxide layer has a thickness of approximately 25 micron. 
     
     
         10 . The implant of  claim 1 , wherein the surface alloyed hardened zone is formed by at least one of the following: oxidation, nitriding, carburizing, and any combination thereof. 
     
     
         11 . The implant of  claim 1 , wherein the surface alloyed hardened zone is formed at approximately 600 degrees C. 
     
     
         12 . The implant of  claim 1 , wherein the substrate is at least one of the following: a cobalt chrome substrate, a titanium substrate, a titanium alloy substrate, a stainless steel substrate, a zirconium substrate, a zirconium alloy substrate, and any combinations thereof. 
     
     
         13 . The implant of  claim 12 , wherein the surface alloyed zone is formed by infusion into the substrate at least one of the following: zirconium, cobalt, chromium, titanium, niobium, aluminum, vanadium, and any combinations thereof. 
     
     
         14 . The implant of  claim 1 , wherein the surface alloyed zone has a thickness of between approximately 2 microns to approximately 2000 microns. 
     
     
         15 . An implant formed by a method comprising:
 forming a surface alloyed zone in a substrate, the forming of the surface alloyed zone including:
 forming a surface alloyed hardened zone by diffusing at least one diffusion hardening material into the substrate; and 
 forming a surface alloyed non-hardened zone by preventing diffusing of the at least one diffusion hardening material into the substrate, the surface alloyed non-hardened zone including no diffusion hardening material. 
   
     
     
         16 . The implant of  claim 15 , wherein the forming of the surface alloyed zone includes forming the surface alloyed zone in a presence of a gas, the gas being at least one of the following: carbon, oxygen, nitrogen, and any combinations thereof. 
     
     
         17 . The implant of  claim 15 , wherein the forming of the surface alloyed zone includes forming the surface alloyed zone in a presence of an inert gas, the inert gas being at least one of the following: argon, helium, krypton, neon, nitrogen, and any combinations thereof. 
     
     
         18 . The implant of  claim 15 , the method further comprising removing at least a portion of the at least one diffusion hardening material. 
     
     
         19 . The implant of  claim 18 , wherein the removing includes at least one of the following: grinding, tumbling, glass-beading, shot-peening, grit blasting, polishing, sanding, abrasive slurry, and any combination thereof. 
     
     
         20 . A method, comprising:
 providing a substrate;   diffusing at least one diffusion hardening material into the substrate to form at least a portion of surface alloyed zone, the surface alloyed zone including:
 a surface alloyed hardened zone including the at least one diffusion hardening material; and 
 a surface alloyed non-hardened zone not including the at least one diffusion hardening material.