Effect of rare earths surface treatment on tribological properties of carbon fibers reinforced PTFE composite under oil-lubricated condition

The effect of rare earths (RE) surface treatment of carbon fibers (CF) on tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites under oil-lubricated condition was investigated. Experimental results revealed that RE treated CF reinforced PTFE (CF/PTFE) composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air-oxidated composites. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that, after RE treatment, oxygen concentration increased obviously, and the amount of oxygen-containing groups on CF surfaces were largely increased. The increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with PTFE matrix, and large scale rubbing-off of PTFE be prevented, therefore, tribological properties of the composite was improved.