Effect and mechanism of new filler on friction and wear properties of high friction composites

High friction composite materials were prepared by dry-hot molding process. The effects of proportion of mass ration of cashew oil modified phenolic resin to nitrile rubber, and the high performance filler (Main components are graphite powder, Al₂O₃、MoS₂ and Fe powder) on the tribological performances of high friction composite materials were studied, respectively. The friction and wear behaviors of the composites were evaluated using a ring-on-block test rig. The worn surfaces and wear debris of high friction composites were analyzed by means of Laser Scanning Confocal Microscopy, SEM and EDS. The results show that the heat resistance and the adhesion are improved with the increasing of mass ratio of CPR to NR, which ensures good friction and wear properties. When the high performance filler content is low, a large number of wear surface and continuous real contact plateaus are formed on the wear surface, and the wear mechanisms are abrasive wear and adhesive wear. When the filler content is higher, the real contact plateaus decreases, severe surface spalling occures and more cracks are formed on the surface, and the wear mechanisms are abrasive wear and fatigue wear. With the increase of high performance filler, the friction surface elemental distribution changes from uniformly distributed to local enrichment, and the size of the abrasive grain gets bigger.