The role of frictional work in tribological behavior of polyamide 66 composites containing rice bran ceramics particles or glass beads

In this study, we investigated tribological behavior of polyamide 66 (PA66) composites containing rice bran ceramics (RBC) particles or glass beads (GBs) under a wide range of contact pressures and sliding velocities, and discussed the role of the frictional work in the behavior. The volume fractions of the fillers were 8 and 26 vol%. The friction coefficients of pure PA66 showed the increasing tendency with the Pv values. In contrast, those of the PA66/RBC composites showed approximately no change, and those of the PA66/GB composites slightly decreased with increasing Pv value. The surface temperatures of the materials increased with increasing frictional work. The maximum temperature of pure PA66 and the PA66 composite with 26 vol% RBC particles exceeded 80 °C, which were higher than the glass transition temperature of PA66 resin. Pure PA66 exhibited a decrease in specific wear rate with increasing frictional work even as a change of the wear mode. This change was considered to be caused by softening of the resin because of high frictional work. In contrast, the specific wear rates of the PA66 composites with the RBC particles or GBs were much lower (<0.5× 10−8 mm2/N) compared with pure PA66 at low frictional work (<1.3 MJ/(m2∙s)). At high frictional work (>1.4 MJ/(m2∙s)), the PA66 composites with the RBC particles showed relatively high specific wear rates (0.6–1.0 × 10−8 mm2/N) because of high surface temperature