Effect of Counter-Surface Texturing on the Tribological Behavior of Virgin and Glass-Filled Polytetrafluoroethylene During Sliding Against Grey Cast Iron

In this research study, the effect of laser surface texturing on the tribological performance of a composite of polytetrafluoroethylene with 25 wt.% glass fibre against grey cast iron was studied. Dimples (50 µm diameter) were ablated on grey cast iron with dimple pitches of 100 µm and 150 µm. Friction and wear tests were conducted on a pin-on-disc tribometer under ambient conditions. The specific wear rate of both polytetrafluoroethylene and its composite generally decreased with increasing sliding distance for all grey cast iron surfaces, whether textured or un-textured. The coefficient of friction followed a similar trend for polytetrafluoroethylene but increased for 25 wt.% glass fibre/polytetrafluoroethylene on textured grey cast iron surfaces. Compared to un-textured grey cast iron, polytetrafluoroethylene exhibited a 14.2–16.7% reduction in coefficient of friction and specific wear rate when sliding against grey cast iron with a 150 µm dimple pitch. For 25 wt.% glass fibre/polytetrafluoroethylene, laser surface texturing increased friction but significantly reduced the specific wear rate by 66.6–73.2%. Increasing the dimple pitch from 100 µm to 150 µm further decreased the coefficient of friction and wear. Field Emission Scanning Electron Microscopy micrographs of textured grey cast iron surfaces post sliding against polytetrafluoroethylene revealed polymer debris deposition, which led to the formation of transfer films that contributed to friction and wear reduction. These findings highlight the potential of laser surface texturing in enhancing the tribological performance of polytetrafluoroethylene-based materials, particularly in optimizing wear resistance and friction control through surface texturing.