Studies on the tribological behavior and transfer film–counterface bond strength for polyphenylene sulfide filled with nanoscale alumina particles

Abstract The tribological behavior of polyphenylene sulfide (PPS) composites made with nanoscale particles (also called “nanoparticles”) of Al2O3 was investigated using the pin-on-disk configuration. The volumetric proportions of the filler used were 0%, 1%, 2%, 3%, 5%, and 10%. The counterfaces were made from hardened tool steel and were prepared with three different surface roughnesses: 0.027, 0.060, and 0.100 μm Ra. Flexure tests on the composite specimens were run to investigate the effect of weakening from the presence of heterogeneous particles and strengthening because of the addition of a harder phase. The lowest wear rate was obtained for the composite with 2 vol.% filler and the counterface with 0.060 and 0.100 μm Ra roughness. The composites with 3 vol.% or greater filler proportions had higher wear rates in all cases. The coefficient of friction was also higher than that of PPS for all composites except with 10 vol.% alumina sliding on a 0.060 μm counterface. The bond strength between the transfer film and the counterface was measured and related to wear rate. It was found that the transfer films with stronger bond strengths led to lower wear for all the composites. The results have been interpreted in terms of the ability of nanoscale particles to anchor the transfer film to the counterface thereby increasing bond strength and lowering wear.