Surface and near surface hardened medical implants

A surface hardened medical implant comprising a zirconium-containing titanium alloy, the surface hardened implant produced by a process comprising:

• (a) subjecting zirconium-containing titanium implant substrate to an environment able to provide oxygen;
• (b) heating the zirconium-containing implant substrate to a temperature that allows oxygen to diffuse into surfaces of said implant;
• (c) soaking the zirconium-containing implant substrate at the temperature for a time sufficient to oxidize elemental metal at the surfaces of the implant substrate;
• and
• (d) producing a hardened medical implant comprising a hard mixed-oxide surface layer on the zirconium-containing implant substrate and an oxygen-rich layer beneath said mixed oxide surface layer.

A medical implant comprising a zirconium-containing core and a hard mixed oxide surface on said core, the implant produced by a process comprising:

• (a) subjecting an implant substrate comprising a zirconium-containing titanium alloy to an environment able to provide oxygen for oxidizing elemental metal at surfaces of the substrate;
• (b) heating the implant substrate in the environment to a temperature from about 200.degree. to about 1200.degree. C.;
• (c) soaking the implant substrate at a temperature that permits oxidizing of elemental metal at substrate surfaces and diffusion of oxygen beneath the substrate surfaces;
• and
• (d) producing a hard mixed-oxide surface layer on the zirconium-containing implant substrate and an oxygen-rich layer beneath said mixed oxide surface layer.