Transfer film growth of continuous carbon fiber reinforced thermoplastic poly(ether ether ketone) facilitated by surface texture during dry sliding

To show the effect of surface texture on transfer film growth of continuous carbon fiber-reinforced thermoplastic poly(ether ether ketone) (CCF-PEEK), tribological behaviors of untextured and laser-engraved-dimple-textured WC–Co, TiN and DLC surfaces dry-sliding against CCF-PEEK pin were studied in ambient atmosphere (pv = 0.46 MPa•m/s). Little tribo-film formed on untextured WC–Co, TiN and DLC, but continuous, relatively uniform CCF-PEEK transfer films with micron-level thickness grew from the majority of dimples along the sliding direction on textured WC–Co, TiN and DLC. A stable reduction in coefficient of friction by nearly 38.3% was achieved by textured WC–Co compared to the untextured. Texturing also yielded significant friction reduction to TiN, but almost did not lower the friction of DLC. Micro-cutting effect from the dimple texture edges probably caused considerable material removal of the counterpart CCF-PEEK pin and the repetitive friction cycles shaped the CCF-PEEK wear debris into the tribo-films. The friction reduction could be primarily attributed to the substantial mediation of tribological CCF-PEEK transfer films on the sliding interface. This study indicates that surface texture can facilitate the growth of polymeric transfer films with tribological application potentials in dry-sliding conditions.