Microstructure And Properties Of Graphene Reinforced Copper Matrix Composites

Graphene-enhanced copper matrix composites have excellent overall performance and broad application prospects.It is the key to the development of graphene-enhanced copper matrix composites that the graphene is more uniformly dispersed in the copper matrix and the wetting of the graphene and copper matrix is improved.In this paper,redox method was used to prepare graphene oxide solution.Graphene was dispersed into copper particles by solution mixing method and ball milling method.GR/Cu composites were prepared by vacuum hot-pressing sintering.The content of graphene was studied for GR/Cu composite.Material microstructure and mechanical,thermal,electrical and wear resistance effects.On this basis,nickel-modified graphene was added to the copper powder and a nickel-plated GR/Cu composite was prepared by vacuum hot-pressing sintering process.The content of nickel-coated graphene was studied on the microhardness and conductivity of the GR/Cu composite.Rate,thermal conductivity,and friction and wear properties.The main findings are as follows:(1)The microhardness of GR/Cu composites increases first and then decreases with the increase of graphene content.When the graphene content is increased to 0.3wt.%,the hardness value of the GR/Cu composite is the highest,which is 80.1HV,which is 12.8%higher than that of pure copper.The conductivity of GR/Cu composites decreases with the increase of graphene content.The wear of GR/Cu composites decreased first and then increased.When the content of graphene was 0.3wt.%,the wear of GR/Cu composites was the lowest,and the abrasion loss of pure copper was 32.3%.The wear mechanism of pure copper is mainly the wear of the exfoliation layer.When the content of graphene is less than 0.3wt.%,the wear mechanism of GR/Cu composite material is the coexistence of abrasive wear and exfoliation wear,when the content of graphene is more than 0.5wt.%The wear mechanism of GR/Cu composites is peeling wear.(2)The microhardness of the nickel-plated GR/Cu composites increases first and then decreases with the increase of graphene content.When the graphene content is 0.3wt.%,the hardness of the nickel-plated GR/Cu composites reaches the maximum value.It is 86.9 HV,which is 22.4%higher than that of pure copper and 8.5%higher than that of GR/Cu composite with the same graphene content.The electrical conductivity of nickel-plated GR/Cu composites decreases with the increase of graphene content.The thermal conductivity of nickel-plated GR/Cu composites increases first and then decreases with the increase of graphene content.When the content of nickel-coated graphene is 0.15wt.%,the thermal conductivity of nickel-plated GR/Cu composites is the highest.The wear of Ni-plated GR/Cu composites decreases first and then increases with the increase of graphene content.When the content of graphene is 0.3wt.%,the wear amount reaches a minimum value,and the wear resistance is good.The amount was 75.2%lower than that of pure copper,62.7%lower than that of GR/Cu composite with the same graphene content.The wear mechanism of 0.3wt.%Ni-plated GR/Cu composites is abrasive wear,and the 0.3wt.%Ni-plated GR/Cu composites have smaller wear debris size,which is more uniform than 0.3wt.%GR/Cu composites.