Increasing of functionality of c.p. titanium/UHMWPE tribo-pairs by thermodiffusion nitriding of titanium component

The tribological characteristics of GRADE 2 commercially pure titanium-ultrahigh molecular weight polyethylene (UHMWPE) medical friction pairs in artificial hip-joints, the titanium working surface of which has been modified by thermodiffusion nitriding to ensure its service ability, have been studied. The efficiency of this pair is mainly related to the fact that, pure titanium, practically, is a material biocompatible with human body tissues. It has been shown that, the use of a step-by-step regime of nitriding, with subsequent polishing of the nitrided GRADE 2 titanium surface for surface hardening, decreases the wear of the UHMWPE component by a factor of more than two orders of magnitude and the friction coefficient by a factor of 6. In this case, the service efficiency of the nitrided GRADE 2 commercially pure titanium-UHMWPE tribo-component is at the level of the ZrO2 zirconium ceramics, which exceeds the traditionally used in endoprosthetics the CoCrMo-UHMWPE and stainless steel-UHMWPE pairs.