Ion implantation effects on friction and wear of joint prosthesis materials.

The literature contains many results from in vitro friction and wear tests for simulating the behaviour of human joint prostheses. However, they are difficult to correlate, even when they are not contradictory. In friction tests, several friction-mechanisms occur when the Ti-6AI-4V titanium alloy rubs against the UHMWPE polyethylene. Corrosion effects which increase wear happen when the 316L stainless steel is used in Ringer's solution. Ion implantation surface treatments have been performed on these three materials. When the operating conditions were optimized, an important reduction of wear and corrosion was observed. The property improvements are due to structural modifications in a thin layer of the materials.