Diffusion-hardened medical implant

A method of making a surface hardened medical implant comprising the steps of:

• forming said medical implant of zirconium or zirconium alloy;
• and,
• further treating said implant by any one of (a), (b), or (c), wherein (a), (b), and (c) are defined as follows:
• (a) treating said implant in the presence of ceramic-forming species at a temperature of less than 700° C. for greater than 5 minutes;
• and,
• thereafter treating said implant under vacuum or inert gas at a temperature of from 500° C. to 1000° C. for greater than 1 hour;
• (b) treating said implant in the presence of ceramic-forming species at a temperature of from 500° C. to 1000° C.;
• and,
• thereafter treating said implant under vacuum or inert gas at a temperature less than 700° C.;
• (c) treating said implant in the presence of ceramic-forming species at a temperature of less than 700° C.;
• and,
• thereafter treating said implant under vacuum or inert gas at a temperature less than 700° C.

A method of making surface hardened medical implant comprising steps of:

• forming said medical implant of zirconium or zirconium alloy;
• forming an oxide, carbide, nitride, boride or combination thereof, on a surface of said implant at a temperature of from 500° C. to 1000° C. for greater than 2 hours;
• removing the formed oxide, carbide, nitride, boride, or combination thereof;
• and,
• thereafter re-forming an oxide, carbide, nitride, boride, or combination thereof, on a surface of said implant at a temperature of from 500° C. to 1000° C. for greater than 5 minutes.

A method of making surface hardened medical implant comprising steps of:

• forming said medical implant of zirconium or zirconium alloy;
• diffusing oxygen or nitrogen into said implant at a partial pressure of oxygen or nitrogen of less than 0.05 bar and at a temperature ranging from 500° C. to 1000° C. for greater than 2 hours;
• and,
• thereafter oxidizing or nitriding the implant between 500° C. to 1000° C. for greater than 10 minutes.

A method of making a surface hardened medical implant comprising the steps of:

• forming said medical implant of zirconium or zirconium alloy;
• oxidizing or nitriding said implant at a temperature of from 500° C. to 700° C. to form at least a 2 micron thick oxide or nitride;
• and,
• thereafter treating said implant under vacuum or inert gas at a temperature less than 700° C. to retain at least 0.1 microns oxide, to form at least 0.005 microns metallic hardened layer, and to form a diffusion zone having a thickness of at least 2 microns.