Friction and wear performance of polyamide 6 and graphite and wax polyamide 6 composites under dry sliding conditions

The friction and wear performance of pure polyamide-6 (PA-6), 5 wt%, 15 wt% graphite filled polyamide-6 and 4 wt% wax filled polyamide-6 (PA-6+4% wax) sliding against stainless steel under dry sliding conditions were studied using a pin-on-disc tribometer. The influences of filler type, content, applied load and sliding speed on tribological properties were investigated. Tests were carried out at sliding speeds of 0.4, 0.8, and 1.6 m/s and applied load values of 50, 75 and 100 N. Scanning electron microscopy (SEM) was utilised to examine worn surfaces microstructure and wear mechanisms. The results showed that, the friction coefficient for PA6 and PA6 composites increases with the increasing load and sliding speed values while wax filled composite showed insensitivity to the change in load values. In addition, it was observed that their wear rate is highly influenced by sliding speed and insignificantly influenced by the change in applied load values. For the range of materials in this investigation, the lowest wear rate is 6.910(-15) m(2)/N for 4 wt% wax filled PA-6 composite and the highest rate is 2.12 x 10(-14) m(2)/N for pure polyamide-6. The wear mechanism includes transferred film and involves deformation and adhesive wear processes. (C) 2012 Elsevier B.V. All rights reserved.