Preparation And Application Of Graphite Film/Copper Composite Materials With High Thermal Conductivity

With the development of electronic devices to miniaturization,light-weight,integration and high-frequency,the power density and heat generation of electronic components are increasing.The heat dissipation has become a key factor of the further development in the electronic industry.As a new type of heat dissipation material,graphite film has been widely used in the field of heat dissipation of electronic products.However,due to the low vertical thermal conductivity and poor mechanical properties of graphite film,the application range is greatly limited.In order to improve the above problems,in this dissertation,we used graphite film as raw material to prepare graphite film/copper composite by plasma modification and electrodeposition technique in the laboratory.The microstructure of the composite was characterized and analyzed,and its vertical thermal conductivity,hardness,yield strength and actual heat dissipation effect were tested and evaluated.Through the above research work,we have solved the engineering problems of electroplating on the surface of graphite film and binding ability between copper thin film.Moreover,we conducted the research and development of the composite material pilot test,and realized the continuous production of the coiled graphite film/copper composite in the pilot test.The main contents and conclusions of this dissertation are as follows:(1)High thermal conductivity graphite film/copper composites were prepared by plasma surface modification and electrodeposition.It was showed that when the air is used as the processing atmosphere,the discharge power is 60 W,the processing time is 30 s,and the gas flow rate is 0.4 L/min,the surface of the graphite film has the best hydrophilicity effect.Under this condition the surface roughness of graphite film increased and the oxygen-containing functional groups was introduced.In addition,the best process parameters for preparing the graphite film/copper composite by electrodeposition are:current density 1.0?1.5 A/dm2,current time 150 s?250 s and the better the hydrophilicity of the graphite surface,the stronger the adhesion between the coating and the copper coating.(2)The microstructure of the composite were characterized and the thermal conductivity,hardness,yield strength.Moreover,the cooling effect of graphite film/copper composite was tested and analyzed.It was showed that when the electrodeposition time is 150 s and 250 s,the surface of the graphite film is completely coated with copper coating.The prepared graphite film/copper composite is composed of graphite and copper,without CuO?Cu2O and other substances.Its vertical thermal conductivity,hardness,yield strength and actual heat dissipation effect are superior to graphite film.They all indicated that the film/copper composites prepared in this work has great potential application in the thermal management field of electronic products.(3)Based on the above study,the technics route is further perfected and the process parameters are optimized.A set of engineering automation pilot production line is designed by ourselves,and the research and development of the test test of graphite film/copper composite material are carried out.The practical problems encountered in the pilot test of graphite membrane/copper composite materials were analyzed and studied one by one through the industry-University-Research Collaboration.In solving the graphite film single-sided plating process exudate,constant tension transmission and coating thickness uniformity control in continuous electrodeposition,we have achieved the pilot production of 90 m and 160 mm coil graphite film/copper composite materials,achieving the purpose of higher yield and continuous production.