| Graphite / copper composite materials have excellent electrical and thermal conductivity and anti-friction and wear resistance,and are widely used in electrical contact materials,electronic packaging materials,self-lubricating materials and brush slides.However,due to the low compatibility,poor wettability,and large differences in physical properties between the copper matrix and graphite,it is easy to cause problems in the prepared C / Cu composites,such as weak contact interface bonding,high internal pores,and poor graphite dispersion.Therefore,it is necessary to modify the surface of the graphite particles and improve the mixing process to improve the interface wettability between graphite and the copper matrix,improve the dispersion of graphite in the copper matrix,and enhance the synthesis of C / Cu composite materials.performance.In this paper,the graphite dispersion liquid is dispersed by ultrasound,and the graphite is evenly dispersed between the copper powder particles by the magnetic stirring combined with the two-step mixing method of high-energy ball milling,and the C / Cu composite material with excellent comprehensive performance is prepared by SPS sintering.The effects of preparation process parameters(ball milling time,sintering temperature)on the microstructure and relative density,electrical conductivity and hardness of the composite materials were studied.In this process parameters studied and non coated graphite coated graphite content of Microstructure on the C / Cu composite material,the relative density,electrical conductivity,hardness and tribological properties.The main findings are as follows:(1)As the increase of the ball milling time,the composite powder is continuously refined and gradually distributed evenly.After SPS sintering,the composite has a dense structure and good interface bonding.With the extension of the ball milling time,the grain size gradually decreases and the graphite distribution becomes more uniform.The hardness of the composite material decreases first and then increases with the increase of the ball milling time,while the conductivity gradually decreases with the increase of the ball milling time.At 8 h of ball milling,the grains were fine and the graphite dispersed evenly.The hardness reached a maximum of 61.4 HV,the electrical conductivity was 87.7% IACS,and the overall performance was the best.(2)As the increase of the sintering temperature,the relative density,electrical conductivity and hardness of the composite material tend to increase first and then decrease.When the sintering temperature is 750 ?,the composite material is dense and the graphite is evenly dispersed.The relative density,electrical conductivity and hardness reach the highest values,which are 98.78%,89.4% IACS and 63.9 HV respectively.(3)As the graphite content increases,the relative density and hardness of the composite materials show a trend of increasing first and then decreasing;while the conductivity and friction coefficient show a trend of gradually decreasing.When the graphite content is 1.0wt.%,the relative density reaches 98.78%,the hardness is 63.9 HV(respectively increased by 0.7% and 1.9% compared to pure copper);the electrical conductivity is 89.7%IACS.The average coefficient of friction is 0.119,which is 52.0% lower than that of pure copper sample 0.248,and the overall performance is the best.(4)As the graphite content increases,the particle size of the copper-plated C/Cu composite powder gradually decreases and the graphite dispersion is relatively uniform.The relative density,electrical conductivity,hardness,and friction coefficient of copper-plated C/Cu composites have gradually decreased.When the graphite content is 1.0wt.%,the grain size of the copper-plated C/Cu composite is fine and the graphite distribution is more uniform,the relative density is 99.91%,the conductivity is 92.1%,the hardness is 67.7 HV,and the friction coefficient is 0.114.Compared with the same graphite content C/Cu composite materials,they were increased by 1.1%,2.7%,5.9%,and-4.2%,respectively,and the overall performance was significantly improved. |
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