Ultra-passivation of chromium containing alloy and methods of producing same

Abstract

The invention concerns article having a surface oxide layer up to 20 nm thick, the surface oxide layer comprising chromium and cobalt oxides where the atomic ratio of Cr/Co is more than 3. The invention also concerns methods for treating a chromium containing material, said method comprising contacting said material with a gas plasma under conditions effective to oxidize at least a portion of the material; and contacting said material with an acid. The treated surface is corrosion resistant and can be used in orthopedic implants, especially the wear surface of the orthopedic implant to reduce wear, and other corrosive environment.

1 - 17 . (canceled) 
     
     
         18 . An chromium containing article having a surface oxide layer up to 20 nm thick, said surface oxide layer comprising chromium and cobalt oxides where the atomic ratio of Cr/Co more than 3. 
     
     
         19 . The article of  claim 18 , wherein said surface oxide is 2.5-8 nm thick and Cr/Co ratio is 3-7. 
     
     
         20 . The article of  claim 18  that is implantable into a mammal. 
     
     
         21 . The article of  claim 20 , wherein said article is a joint replacement prosthesis or component thereof. 
     
     
         22 . The article of  claim 21 , where said article is a hip or knee replacement prosthesis. 
     
     
         23 . The article of  claim 22 , wherein said surface is at a wear interface. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled)