Tribological properties of lanthanum treated carbon fibers reinforced PTFE composite under dry sliding condition

The effect of rare earth (RE) surface treatment of carbon fibers (CF) on bending strength and tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites was investigated. Experimental results revealed that the bending strength of CF reinforced PTFE (CF/PTFE) composite was largely improved by RE treatment. Compared with the untreated and air-oxidized CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under various applied loads and reciprocating sliding frequency. Scanning electron microscope (SEM) investigation showed that RE treated CF/PTFE composite had smooth worn surface under given load and sliding frequency, and a continuous and uniform transfer film formed on the counterface of the composite, which helped to reduce the wear of the counterpart. The improvement in bending strength and tribological properties of CF/PTFE composite may due to an improvement in interfacial adhesion between CF and PTFE after RE treatment. The strong interfacial coupling of the composite made CF not easy to detach from the PTFE matrix, and prevented the rubbing-off of PTFE, accordingly improved the friction and wear properties of the composite.