Investigation of the tribological properties of polyfluo wax/polyurethane composite coatings filled with several micro-particulates

The tribological properties of the polyfluo wax (PFW)/polyurethane (PU) composite coatings filled with micro-MoS2, graphite and SiO2 were investigated using a ring-on-block wear tester under dry friction condition, and the worn surfaces of the composite coatings and transfer films formed on the surface of the counterpart steel ring were respectively investigated by SEM and optical microscope. The chemical changes of the composite coating filled with 10 wt.% MoS2 during the wear process were analyzed by XPS and FTIR. It was found that the additions of MoS2, graphite and SiO2 are effective in enhancing the wear life of the PFW/PU coatings. Especially, the coating filled with 10 wt.%. MoS2 can obtain the best anti-wear ability. Meanwhile, we studied the effect of curing temperature, sliding speed and applied load on the friction and wear behaviors of the PFW/PU composite coatings filled with several particulates. The results showed that the coatings filled with several particulates have excellent anti-wear behaviors as curing temperature is below 120 °C, and all coatings have the best anti-wear ability at 2.56 m/s and 320 N. Furthermore, the tribochemical studies by XPS revealed that MoS2 in the PFW/PU composite coating is translated to MoO3 during the wear tests. Accordingly, IR analyses indicated that the occurrence of the tribochemical changes during friction process mainly involved disordering and partial decomposition of the polyurethane binder.