Influence of water absorption on friction, wear and abrasion resistance of PA6-hBN composites

Abstract

Investigations on the tribological properties, i.e., abrasion resistance, friction coefficient, and wear of water conditioned polyamide6/hexagonal boron nitride composites were carried out in this research. Polyamide6 and polyamide6/hexagonal boron nitride composites were fabricated with the help of a twin-screw extruder and injection moulding machine. Fabricated materials were water immersed for 15 days to analyse the effect of water absorption on the tribological properties of materials. Tribological tests were carried out on a pin-on-disc tribometer, and abrasion resistance tests were performed on a TABER abrader. The SEM analysis was carried out to analyse the wear tracks of water conditioned composites. Testing on TABER abrader revealed the loss in abrasive resistance of composite materials, while tribological testing of composites with steel as the other mating and rubbing surface revealed improvements in COF and wear after water absorption. The SEM images revealed less depth of wear in water conditioned materials compared to dry ones. The causes of wear were found as the stick and slip, i.e., adhesive wear in which material tends to stick during matting with steel disc, and due to the continuous movement, it slips. Water absorption was found supportive in the formation of smooth lubricating transfer film on a steel disc. Bonding between the polyamide matrix and water molecules plus the formation of boric oxide & orthoboric acid were found advantages in decreasing the friction coefficient and wear of water conditioned composites.