Tribological behavior of UHMWPE against TiAl6V4 and CoCr28Mo alloys under dry and lubricated conditions.

This work is focused on the study of the tribological behavior of TiAl6V4 and CoCr28Mo against UHMWPE. Wear tests were achieved on a reciprocating pin-on-disc tribometer under dry and lubricated conditions. Four bio-lubricants were retained namely: saline solution (NaCl 0.9%), sesame oil, nigella sativa oil and Hyalgan® which is a pharmaceutical intra-articular injection containing sodium hyaluronate active agent (20mg/2mL). The coefficient of friction and wear volume of UHMWPE were evaluated after tribological tests. It is found that, the friction and wear behaviors of CoCr28Mo/UHMWPE pair under dry and bio-lubrication were the best. Results show that the use of natural oils improved significantly the tribological behavior of CoCr28Mo/UHMWPE and TiAl6V4/UHMWPE pairs. Microscopic and chemical analyses of wear tracks on UHMWPE were carried out and wear mechanisms were proposed for each materials pair. The tribological performance of the used oils was linked to their chemical composition and to their adsorption ability on the metallic surfaces.