Co-Cr-Mo alloy is used as a femoral head of joint
prostheses in conjunction with an ultra high molecular
weight polyethylene (UHMWPE) cup because of the high
wear and corrosion resistance of this alloy. The problem with
the metal-on-metal couple is that the release of metal ions is
higher than that of the polymer-on-metal couple in in vivo,
which will, over many years lead to toxicity problem. The
metal ions dissolved from Co-Cr-Mo alloy powder bind
serum proteins to a much greater level compared to that of
Ti-6Al-4V alloy. The conventional Co-29Cr-6Mo-1Ni alloy
(ASTM F75-92) contains 1 mass% of Ni and the Ni and Co
ions are responsible for allergic reactions. Especially, Ni