Friction and wear characteristics of ultrahigh molecular weight polyethylene (UHMWPE) composites containing glass fibers and carbon fibers under dry and water-lubricated conditions

The effects of introducing glass fiber (GF) and/or carbon fiber (CF) filler materials on the friction and wear characteristics of ultra-high molecular weight polyethylene (UHMWPE)-based composites were investigated. The composites were evaluated against GCr15 steel under dry and water-lubricated conditions. The goal was to develop an improved material for water-lubricated journal bearings. The friction coefficients of UHMWPE composites were obtained using a pin-on-disc tribometer using sliding speeds ranging from 0.2 to 1.0 m/s, contact pressures from 1.0 to 5.0 MPa, and two counterface roughness values (Ra=0.1 and 0.3 μm). The samples were lubricated by dropping distilled water onto the sliding surface. To evaluate the wear mechanisms, the morphologies of the worn surfaces were examined by scanning electron microscopy and laser 3D micro-imaging profile measurements. In addition, the elemental distribution and content in the transfer film on the GF/UHMWPE composite surface were measured using an energy-dispersive X-ray spectrometer. The results show that glass fibers could effectively reduce the wear rate of composites. In addition, a hybrid filling of glass and carbon fibers could significantly reduce the friction coefficient under water lubrication and dry conditions.