Influence of Porosity on the Mechanical and Tribological Properties of Porous ATP / GF / UHMWPE Water‐Lubricated Bearing Composite Materials

ABSTRACT To improve the tribological properties of ultra‐high molecular weight polyethylene (UHMWPE) water‐lubricated bearing composites, attapulgite (ATP)/glass fiber (GF)/UHMWPE composites were modified into porous materials using NaCl as a porogen. The porosity, surface topography, wettability, mechanical and tribological properties of the porous materials with varying porogen contents were examined, as well as their performance in water‐lubricated thrust bearings. The results demonstrate that as porosity increases, the porous composites show better wettability, but reduced hardness and compressive strength. Both the dry friction and water‐lubricated friction coefficients exhibited an initial decrease followed by an increase, with the lowest average values observed at a porosity of 9.9%. Under water‐lubricated conditions, residual NaCl in the porous composites is exposed and leached out during friction, creating new pores. The hydrodynamic effect generated by these pores, combined with the reduced contact area between friction pairs, ultimately endows the porous composites with superior tribological performance in water‐lubricated bearings, outperforming non‐porous counterparts.