Tribological Properties of Vapor Grown Carbon Fibers as Conductive Additive in Grease

A series of conductive greases were synthesized using vapor grown carbon fibers(VGCF), silver and copper powders as conductive additives. The polyethylene oxide polypropylene oxide monobutyl ether(PAG) and polytetrafluoroethylene(PTFE) were used as base oil and thickener, respectively. The GEST-121 surface volume resistance meter was employed to determine the volume resistivity of the grease. The tribological properties were investigated by reciprocating friction and wear tester. Scanning electron microscope and energy-dispersive X-ray spectroscopy were employed to analyze the worn surfaces and typical elements. The result shows that the conductive grease containg VGCF(VGCF grease) had the lowest volume resistivity at room temperature and 100℃. The tribological properties of VGCF grease were the best among the three kinds of prepared greases. When the VGCF content was 1.5%, the tribological performances were the best.