Preparation,Morphology And Structure Study Of Graphene/Copper Composite Powders

With the rapid development of high-tech industries such as delivery vehicles,special equipment,and aerospace,the demand for materials is higher and higher.Therefore,the research on composite materials is increasingly important.Graphene has low density,high mechanical performance,high thermal conductivity and low thermal expansion,and graphene composites quickly attracted munch attention in material research since graphene was found.In the preparation technology of graphene-metal composites,the dispersion of graphene,the interfacial bonding with the matrix,and the retention of graphene structural properties during the preparation process have become the main technical difficulties.In this study,a graphene/copper composite powder was prepared by a"non-addictive"molecular-level mixing method.Graphene oxide and copper acetate serve as the carbon source and the copper source respectively in the preparation of precursor powders by molecular-level mixing method and spray drying technology.Graphene/Copper composites were reduced at H₂ atmosphere through in-situ grown method.The precursor and graphene/copper composite powders were characterized by Zeta potential,laser particle size analysis and X-ray diffraction?XRD?,Raman spectroscopy,scanning electron microscope?SEM?and so on.The results showed that:The structure of the precursor and the conditions of in-situ symbiosis are the key factors for the preparation of graphene/copper composite powders and have a very important influence on the morphology and structure of the graphene/copper composite powders.In the preparation of the precursor composite powder,the molecular-level mixing method causes the copper source and the carbon source to be combined with chemical bonds to generate a strong binding force.Spray drying controls the segregation or agglomeration of the carbon source and the copper source in the precursor to spherical particles with a particle size of 5?m,so that the overall powder composition is uniformly distributed.The graphene/copper composite powder was prepared by the precursor reduction and symbiosis,in which graphene sheets and the copper particles are closely intertwined.The degree of reduction of graphene in the graphene/copper composite powder is as high as 87%.The increased reduction temperature of the graphene/copper composite powder decreases the reduction degree.The particle size distribution of the graphene/copper composite powder is about 10?m,and will the high increase with heating rate and inert gas protection,thus suppressing to the uniform distribution of graphene.This paper systematically studied the influence of graphene content for the morphology and structure of graphene/copper composite powders.The way of combination between graphene and copper has two kinds in the composite powders.When the content of graphene is small,the graphene sheet and copper particles interspersed each other.When the graphene content is high,graphene and Copper intertwined.When graphene content is small,dispersion is dominant.After the graphene content is increased to 1%,the dispersion effect is reduced,and the agglomeration effect becomes prevailing.