Molybdenum alloys for medical devices

A method for using an orthopedic medical device having increased surface hardness and wear resistance comprising:

• providing said orthopedic medical device selected from a joint implant, said joint implant is a knee implant, hip implant, shoulder implant, ankle implant, wrist implant, or elbow implant, said orthopedic medical device having a body that includes a molybdenum-rhenium alloy and a nitride surface layer on an outer surface layer of said molybdenum-rhenium alloy, said nitride surface layer includes nitrogen, molybdenum, and rhenium;
• providing a liner of said joint implant;
• and,
• mating said joint implant with said liner, said nitride surface layer of said orthopedic medical device engages said liner,
• wherein said nitride surface layer is formed by exposing said body that includes a molybdenum-rhenium alloy to a nitriding process in the presence of nitrogen gas or a nitrogen gas mixture for at least about one minute at a temperature of at least about 400° Celsius,
• wherein said nitride surface layer comprises 40-99 wt. % molybdenum, 1-40 wt. % rhenium, and 0.0001-5 wt. % nitrogen, and
• wherein said nitride surface layer a) results in enhanced wear-resistance properties to said orthopedic medical device as compared to a similar molybdenum-rhenium alloy that is absent said nitride surface layer, b) extends a life of said orthopedic medical device, c) increases a wear life of mating surfaces on the orthopedic medical device, and d) reduces particulate generation from use of said orthopedic medical device.