Impact of nanosilica on the friction and wear of a PEEK/CF composite coating manufactured by fused deposition modeling (FDM)

Carbon fiber (CF) reinforced polyethcretherketone (PEEK) coating material on a pure PEEK backing was prepared by using FDM technique towards the aim of studying its tribological properties. Two kinds of tribo-tests were conducted. Firstly, the tribological performance of PEEK/CF coating was evaluated by sliding against a steel ring. In a second attempt, nanosilica was fed into the interface of polymer and steel ring, to study the effect of nanosilica on the tribological properties of the coating. The results demonstrate that friction coefficient and wear rate strongly dependent on the siding direction. Both characteristic values exhibit much lower values, when the sliding took place perpendicular to the carbon fibers. Comparative analyses of the worn surfaces reveal that the great friction and wear reduction can be contributed to the effective distribution of shear stress on carbon fibers. More usefully, taking-in of nanosilica into the interface significantly improves friction performance of the coating material. The responsible mechanisms are rolling of nanosilica in the interface and reduction of adhesion between the tribo-pair due to presence of nanosilica. It is highlighted that oriented short CF reinforced PEEK tribo-coatings can be manufactured thanks to the FDM technique and their tribological performance can be further modified with external nanosilica taking-in into the sliding interface. It is expected that the external nanoparticle donator could be integrated into the composite materials through printing with optimized processing which can prevent formation of defects in the composites.