| Copper based self-lubricating material is composed of copper matrix and lubricating components,which can have the excellent properties of copper matrix and lubricating components.The selection of lubricating components is crucial importance to improve the tribological properties of materials.Graphene interlayer carbon atoms are combined by Van der Waals force,which is easy to slide under low shear stress and has superior lubrication performance.However,graphene is easy to agglomerate and has weak adhesion with copper composite interface.In order to improve the agglomeration of graphene and the interfacial bonding strength with copper,Graphene oxide（GO）coated copper powder and GO coated copper and graphite（C）powder were prepared by electrostatic self-assembly technology in the paper.The effects of various process parameters were explored about the powder coating effects.The composites were prepared by plasma sintering technology（SPS）,and the internal relationship was further explored between the microstructure,morphology,density,hardness and friction and wear properties of the composites The main results are as follows:（1）The effects of modifier types,content,copper powder particle size and graphene oxide content on graphene oxide coated copper powder were studied by adjusting the coating process parameters and using electrostatic self-assembly technology and using the strong hydrogen bond and cationicπ-πinteraction between ionic liquid and graphene oxide.The results show that copper powder modified with 1-butyl-3-methylimidazole tetrafluoroborate（[Emim]+[BF4]-）ionic liquid has the best coating effect on graphene oxide.Graphene oxide can be gradually reduced during heating.The best coating process is that the amount of[Emim]+[BF4]-ionic liquid is 1.5ml（60g copper powder）,and the mass fraction of graphene oxide is 0.5%.（2）Based on the best coating process,graphene oxide coated copper composites were prepared by SPS.The effects of graphene oxide content were studied on the microstructure and properties of graphene oxide coated copper（GO/Cu）.The results show that GO/Cu composites have a certain lubrication effect,but the wear rate increases.This is mainly related to the fact that the lubricating transfer layer formed by graphene oxide is easy to be damaged and difficult to maintain stability due to the small amount of graphene oxide.（3）Graphene oxide coated copper and graphite（GO/C/Cu）composites were further prepared by using the"bridge"effect of graphene oxide between copper and graphite.The results show GO/C/Cu composites have better hardness than single graphite and copper composites.When graphene oxide is 0.5%and graphite content is 2%,the friction and wear performance of GO/C/Cu composite is the best,its friction coefficient is 0.14 and its wear rate is 4.65×10-6mm3/（N×m）.GO/C/Cu composites are mainly subject to slight abrasive wear,which is mainly related to the improvement of graphene dispersion,the close combination of copper and graphite,and the long-time maintenance stable and continuous lubrication layer.When load is 10N and speed is 600r/min,the damage and formation of transfer lubrication layer reach a balance state,the wear rate of composites is the lowest. |
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