Effect of hBN and Calcined Petroleum Coke on Friction and Wear Properties of Phenolic Resin-based Friction Composites

Calcined petroleum coke(CPC) and hexagonal boron nitride(hBN) used as the friction modifiers were filled into phenolic resin-based friction composites.Effects of the friction modifiers on mechanical and tribological properties of friction composites were investigated.Thermal stability of the friction composites was analyzed by means of thermogravimetric analysis(TGA).Worn surfaces of friction composites were examined with a scanning electron microscope to examine wear mechanism of the composites.It was found that inclusion of hBN of at volume fraction 10%~15% contributed to increase the bonding strength and decrease the hardness of the friction composites,and to stabilize the friction coefficient and improve wear resistance of the friction composites.With increase of CPC,mechanical strength of the friction composites increases,while its friction coefficient and wear rate decreased.Incorporation of 12%CPC and 12%hBN is useful to decrease speed and load sensitivity on friction and wear and to improve heat-resistance of the friction composite.12%hBN filled friction composite had the best thermal stability and the smallest speed and load sensitivity on friction and wear as well.