Study on Bio-tribological Properties of Nitrogen Ion Implanted UHMWPE

摘要

As the aseptic loosening induced by polyethylene wear debris is the main cause of long-term failure of total joint replacements, increasing the wear resistance of ultrahigh molecular weight polyethylene (UHMWPE) will be very important to obtain long-life artificial joint. In this paper the UHMWPE was implanted with 450 keV N~+ ions to three doses of 5 x 10~(14)/cm~2, 2.5 x l0~(15)/cm~2 and 1.25 x 10~(16)/cm~2. The friction and wear behaviors of UHMWPE were studied under lubrication of distilled water and blood plasma using a ball-on-disk tribometer with a ZrO_2 ceramic ball as a counterface. Experimental results showed that the friction coefficient of ions implanted UHMWPE are higher than un-implanted UHMWPE. Under blood plasma lubrication condition, the wear rate of implanted UHMWPE was lower than un-implanted UHMWPE, and the wear rate decreased with increasing implantation dose. The plow, plastic deformation and fatigue were wearing mechanism for un-implanted UHMWPE and the abrasive wear for implanted UHMWPE.