The Influence Of Emulsified Pitch On The Structure And Performance Of The Copper-graphite Pantograph Sliding Plate

Copper-Graphite composite is an excellent material with self-lubricating properties.It includes high conductivity and thermal conductivity of copper and excellent lubricity of graphite,and has been applied in many fields.However,because the interface between copper and graphite is only physically mechanical joint,it greatly limited the performance of Cu/G.This paper explored the effect of emulsified asphalt on density,resistivity,hardness,friction and wear properties of Cu/G composite,and discussed its influence mechanism.Finally,it is verified by the first principle calculation.In this paper,Cu/G and copper /graphite /emulsified asphalt composites(Cu/Asp/C)with different graphite contents were prepared by powder metallurgy method.The phases and morphology were characterize by XRD and SEM.Abrasion loss,friction coefficient and worn surface morphology were given by MFT-3000 friction and wear test machine.(1)The XRD results show that the emulsified asphalt has little effect on the phase of composites.(2)From the SEM result,it is found that the interface between copper and graphite of Cu/G is mechanical joint and exist many pores,but on the interface of Cu/Asp/C it appears a thin layer of similar graphene structure,this structure has the features of curl,bend and interlaced arrangement.It indicated that emulsified asphalt will change the interface of Cu/G composite.From the physical properties,it can be seen the density and hardness of composite were decreased,and the resistivity was increased with the increase of graphite content.But after repressing,the density and hardness of composite were increased sharply,and the resistivity was decreased.(3)From friction and wear properties,it is found that with the increase of graphite content and load,the abrasion loss of the composite will increase,and the friction coefficient will decrease.the wear mass of Cu/Asp/C is much less than that of Cu/G under the same condition,especially when the graphite content is 6%.When the graphite content is between 4%-6%,the friction and wear properties of Cu/Asp/C are best and obviously better than that of Cu/G.It indicates that the emulsified bitumen will have a positive effect on the interface of copper graphite composite,andemulsified bitumen can effect the wear mechanism.(4)In this work,the structural stability,electronic of Cu/G and Cu/Asp/C models were investigated by using first-principles calculation.The results show that the small molecules of asphaltene will effect the electronic structure,especially the acridine(AD)molecules.The AD molecules transfer the charge with the Cu(111)and graphite(0001)at the surface,it will improve the bonding properties of the Cu and graphite,which is a good agreement with the conclusion of the experiment.