Fluorinated Modification of Carbon Fibers and Its Synergistic Enhancement With Ag‐Coated Cu Hybrid Microparticles in Polytetrafluoroethylene Composites for Lubricating Bearings

ABSTRACT Carbon fibers are frequently used as reinforcements in polytetrafluoroethylene (PTFE) composites, but weak interfacial bonding limits their bulk performance, which often falls short of that in multi‐filled composites. In this study, a simple fluorinated modification of carbon fibers using different fluorosilanes was developed and used to reinforce PTFE composites together with Ag@Cu hybrid microparticles with high thermal conductivity. The mechanical, thermal, and tribological performance of the developed ternary composites was investigated. The results showed that perfluorodecyltriethoxysilane was effectively grafted onto the fiber surface with a high modification ratio of more than 20%. The fabricated composites typically have tensile strengths greater than 26 MPa with an elongation of ~300% due to enhanced interfacial adhesion. The wear performance was generally enhanced with the fluorinated carbon fibers, being 94.2% lower than that of virgin PTFE. The further incorporation of Ag@Cu helped decrease the wear loss of the CF/PTFE composite by 94.8%, reaching the minimum value of 5.6 × 10 −6 mm 3 /N·m. With the synergistic enhancement of fluorinated carbon fibers and Ag@Cu particles, the PV value of PTFE‐bearing sleeves increases to 3.25 MPa·m/s owing to the improved load‐capacity and thermal dissipation ability.