Study on influence of Koch snowflake surface texture on tribological performance for marine water-lubricated bearings

The ultra-high molecular weight polyethylene (UHMWPE) has become one of the most popular and reliable material for water-lubricated bearings in recent years. In this study, three kinds of new Koch snowflake textures were designed on the surface of the UHMWPE to try to decrease friction and prolong the service life of the bearings. The wear process of the UHMWPE/QSn7-0.2 rubbing pair was analyzed using a specially designed tester under water-lubricated conditions. The analysis results demonstrated the testing velocity and load significantly affected the friction coefficient of the UHMWPE specimens. The UHMWPE specimen without texture-treatment had higher friction coefficient than that of the textured UHMWPE specimens at high velocity, where the maximum rate of increase was 35.2% at the velocity of 350r/min compared with non-texture. The dominant wear mechanism was abrasive wear and slight adhesive wear for the non-texture UHMWPE sample, and the wear mechanism of textured samples was slight abrasive wear. The wear performance of the UHMWPE with composite texture was superior to that of other textures, which was mainly attributed to the micro hydrodynamic bearing effect and stepped bearing effect. As a result, the findings of this work can provide experimental foundation for texture design and optimization on UHMWPE surfaces for better service of the marine water-lubricated bearings.