Preparation And Thermal Performance Analysis Of Graphene/Copper Layered Composite Materials

With the approaching of the era of 5G,power devices continue to develop toward high frequencies and high power,resulting in the continuous increase of power consumption of equipment and the rapid rise of heat generation.In order to solve this problem,more and more thermal conductive materials will be added to the design of electronic products.However,traditional metal thermal conductive materials have been unable to meet the needs of practical applications due to their own heat dissipation capacity defects.Therefore,the development of higher performance composite materials has become an inevitable trend.In this paper,graphite is used as a raw material to prepare highly thermally conductive graphene/copper(Gr-Cu)layered composite materials by a combination of electrophoretic deposition and vacuum hot pressing.The main research contents of this article are as follows:(1)The modified Hummers method was used to prepare stable graphene oxide suspension,and electrophoretic deposition method was used to prepare graphene composite materials(EPD-Cu).The influence of electrophoretic deposition parameters such as suspension concentration,deposition voltage and time on the film-forming properties of the graphene deposit was studied,and the best graphene film-forming process was established.The analysis of microstructure and structure confirmed that the electrophoretic deposition process can effectively introduce graphene on the copper substrate.(2)In order to improve the thermal performance of EPD-Cu composite materials,it is processed by vacuum hot pressing to obtain Gr-Cu composite materials.Furthermore,the effects of different vacuum hot-pressing pressures and temperatures on the interface and thermal conductivity of Gr-Cu composites were studied and the optimal vacuum hotpressing parameters were established.The microstructure and structure of Gr-Cu composites were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).The results show that the vacuum hot pressing process can help the ordered arrangement of the graphene layered structure and repair the defects of the graphene,thereby further improving the thermal conductivity of the composite(3)Gr-Cu composites were prepared under the optimal process parameters,and the effect of graphene content on its microstructure and thermal properties was studied.In this paper,SEM,XRD and X-ray diffraction electron spectroscopy(XPS)analyzers are used to characterize the phase composition,structure and morphology of the composite materials.The thermal expansion coefficient and thermal conductivity of the material are tested.The results show that when the graphene content is 1.6 vol%,the Gr-Cu composite has dense layered junctions,the thermal conductivity is increased by 80%,and the thermal expansion coefficient is reduced by 28.1%.In addition,in order to analyze the actual heat dissipation effect of Gr-Cu composite materials,different heat dissipation experiments were designed in this paper.The test results show that the Gr-Cu composite material exhibits excellent heat transfer ability,especially under high temperature environment.