Tribological Mechanism of Ultra‐High Molecular Weight Polyethylene Reinforced by Nano‐Silica Under Water Lubrication Conditions

Ultra‐high molecular weight polyethylene (UHMWPE) is widely used in water‐lubricated bearings due to its excellent self‐lubricating properties. However, its low wear resistance limits its broader application. UHMWPE filled with nano‐silica (nano‐SiO 2 ) has been proven effective in improving its tribological properties, but the underlying mechanisms remain unclear. Herein, the hydroxyl groups of nano‐SiO 2 were modified by the silane coupling agents 3‐methacryloxypropyltrimethoxysilane (SiO 2(570) ) and 3‐aminopropyltriethoxysilane (SiO 2(550) ), respectively. Then, they were filled into the UHMWPE. Frictional tests were conducted between the composites and ZCuSn 10 Zn 2 under water lubrication conditions. The results showed that the different interfacial interplay between nano‐SiO 2 and UHMWPE makes for distinct wear mechanisms. The SiO 2(550) ‐filled composite demonstrated a significant reduction in wear rate, attributable to its superior ability to restrict the movement of UHMWPE molecular chains. However, the friction coefficient increased for all composites due to the modified SiO 2 hindering the formation of a complete water film.