The effect of the addition of graphite on tribological properties of glass fibre-reinforced polyimide composites

Abstract

The glass fibre (GF)-reinforced polyimide (PI) composites filled with graphite powders were fabricated by means of hot press moulding technique. The friction and wear properties of the resulting composites sliding against GCr15 steel were investigated on a model ring-on-block test rig at dry sliding condition. The wear mechanisms were also discussed based on scanning electron microscopic examination of the worn surface of the PI composites and the transfer film formed on the counterpart. With the increasing normal loads, the friction coefficient of the composites decreased under the dry sliding, owing to inconsistent influences of shear strength and real contact areas. Experimental results revealed that the incorporation of graphite significantly improves the wear resistance of the GF-reinforced PI composites. For best combination of friction coefficient and wear rate, the optimal volume content of graphite in the composites appears to be 30 per cent.