A novel hybrid polymer nanocomposite coating of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with nanoclay (C15A) and carbon nanotubes (CNTs) has been developed to protect metallic mating surfaces in tribological applications. The hybrid nanocomposite coatings were deposited on aluminum substrates using an electrostatic spraying technique. Ball-on-disk wear tests using a 440C stainless steel ball as the counterface were conducted on the coatings under dry conditions to determine the optimum amount of the loadings of the nanofillers and evaluate their tribological performance at different normal loads and linear velocities. Micro-indentation, raman spectroscopy, scanning electron microscopy (SEM), and optical profilometry techniques were used to characterize the coatings in terms of hardness, dispersion of the nanofillers, morphology, and wear mechanisms, respectively. Results showed that the UHMWPE hybrid nanocomposite coating reinforced with 1.5 wt % of C15A nanoclay and 1.5 wt % of CNTs did not fail even until 100,000 cycles at a normal load of 12 N and a linear speed of 0.1 m/s showing a significant improvement in wear resistance as compared to all other coatings evaluated in this study.

The effect of various operational factors, such as sliding speed, normal load and temperature on the tribological properties of Date palm fruit syrup (DPFS) as an environmentally friendly lubricant, is investigated. Ball-on-disc wear tests are conducted on mild steel samples in the presence of DPFS as a lubricant under different conditions and the coefficient of friction and wear rate are measured. Scanning electron microscopy, stylus profilometry, and Fourier transform infrared spectroscopy are used to evaluate the wear tracks to determine the underlying wear mechanisms. Results showed that DPFS has excellent tribological properties in terms of low friction and low wear rates making it a potential candidate to be used as a lubricant in tribological applications.