Effect of graphite content on friction and wear properties of automotive Ni-coated graphite/Cu composites
The amount of graphite added is one of the key factors affecting the tribological properties of Cu matrix composites.The influence of Ni-coated graphite content(2,4,6 and 8 mass％)on tribological behavior of Ni-coated graphite/Cu composites was studied.The relationship between the graphite content and the microstructure,physical properties and hardness of the composites was analyzed to determine the optimal amount of graphite added.The results show that the bonding between graphite and Cu in the composites is good,and there are no obvious voids or cracks.As the Ni-coated graphite content increases from 2 mass％to 8 mass％,the density and conductivity of the composites decrease by 3.7％and 43.5％,respectively,the hardness first increases from 60.3 HVO.1 to 63.4 HVO.1 and then decreases to 59.7 HV0.1,with a turning point at 6 mass％Ni-coated graphite,and the friction coefficient and wear rate both decrease first and then increase.Therefore,the optimal amount of Ni-coated graphite added is 6 mass％.At this time,the wear mechanism of the composites is mainly abrasive wear,accompanied by adhesion and oxidation wear.
Cu matrix compositesNi-coated graphitewear mechanism
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