Fretting Wear Behavior of Cu/Ultra-High Molecular Weight Polyethylene Nanocomposites Under Different Strokes

Ultrahigh molecular weight polyethylene (UHMWPE) composites reinforced with various contents of nanometer sized particles of Cu were prepared by a hot pressing technique. The fretting wear behavior of UHMWPE and the Cu/UHMWPE nanocomposites were evaluated on an oscillating reciprocating friction and wear tester. The study focused on the effect of the Cu nanoparticle contents and the fretting strokes on the fretting wear behavior of the composites. The results showed that both the strokes and the contents of Cu nanoparticles had an influence on the tribological properties of the composites. The friction coefficients and wear rates first decreased and then increased with the increasing of Cu nanoparticles contents. The content corresponding to the lowest friction coefficient was 1.5%. When the amounts of Cu nanoparticle ranged from 0.5% to 1%, the composites showed the lowest wear rates. In general, the higher number of strokes corresponded to the lower wear rates, which were attributed to alleviated abrasion. More importantly, thin and uniform transfer films were formed on the worn surfaces of the steel balls after sliding against the 1% Cu/UHMWPE nanocomposites. Consequently, the wear rate was decreased. It was inferred that the inclusion of Cu nanoparticles is beneficial for improving the wear resistance of the composites.