Effects of TiO2 nano-particles on wear-resistance and vibration-reduction properties of a polymer for water-lubricated bearing

Water-lubricated bearings play a vital role in improving the energy efficiency and environmental friendliness of ships. However, under the operating conditions such as start-stop and steering, the ship’s stern bearing is often in boundary-lubricated or even dry friction condition due to the weak load-bearing capacity of the water film between the ship's drive shaft and the stern bearing. Therefore, the design of a polymer material with a low coefficient of friction and low vibration amplitude in both water-lubricated and dry friction conditions can greatly improve the stability and safety of the ship's operation. As a common reinforcing filler, TiO2 nanoparticles have a notable enhancement effect on the tribological properties of lubricants. Therefore, in this paper, the tribological behaviors between UHMWPE matrix reinforced with TiO2 nanoparticles and zirconia ceramic ball were investigated and the frictional vibrations during the friction process were analyzed. The results showed that TiO2 generated a ball-bearing effect on the surfaces of the friction pair, which led to a smooth and flat wear surface and reduced the friction and vibration behaviors. The modified composite with 0.9 wt.% TiO2 exhibited the best tribological and vibration-absorbing properties in both water-lubricated and dry friction conditions. This study helps to provide a theoretical foundation for the design of marine water-lubricated bearing materials with excellent wear-resistance and vibration-reduction properties.