Preparation Of Ag@CNTs By Sonochemical Method And Research On The Properties Of Its Reinforced Copper-based Composite

Carbon nanotubes（CNTs）are considered to be one of the most suitable reinforcements for the preparation of copper matrix composites.However,actual studies have found that the weak interfacial bonding between CNTs and copper matrix and the uniformity of CNTs dispersion are the main reasons why the performance of CNT/Cu composites often cannot reach the ideal value.A large number of studies have shown that surface metal modification of CNTs is an effective method to improve the interfacial bonding and the uniformity of CNTs dispersion.In this paper,nano-silver modified carbon nanotubes（Ag@CNTs）were prepared by sonochemical synthesis,and then based on the powder metallurgy process route,Ag@CNTs/Cu composites were prepared by ball milling and spark plasma sintering.Characterization,testing and analysis were performed.The main content and results of this paper are as follows:（1）The Ag@CNTs composite powder was prepared by pretreatment of CNTs and then ultrasonic chemical synthesis,and the preparation process of Ag@CNTs was studied.The research co MParison found that when the ultrasonic reaction time is 30min,the PVA concentration is0.5g/L,and the ratio of M_CNTs:M_{Ag NO3} is 1:2,Ag NPs can be uniformly decorated on the surface of CNTs,and the uniform size is about 5nm,and the thermal gravimetric analysis（TGA）It was found that the mass ratio of Ag NPs in Ag@CNTs was about 15.2%.（2）Ag@CNTs/Cu composites were prepared by adding Ag@CNTs prepared by ultrasonic chemical synthesis as the reinforcing phase into Cu powder by powder metallurgy.Compared with the CNTs/Cu composites,Ag@CNTs improved the dispersion and interfacial bonding in the Cu powder.Through tensile experiments on Ag@CNTs/Cu composites prepared with different volume fractions of Ag@CNTs,the results show that the UTS of Ag@CNTs/Cu（315MPa）composites is significantly higher than that of pure Cu（227MPa）and CNTs/Cu（198MPa）composites when the volume fraction of Ag@CNTs is 0.9vol.%,and the Ag@CNTs/Cu（0.9vol.%）composites still maintain the electrical conductivity of 94.9%IACS（3）The effects of different Ag@CNTs volume fractions on the thermal conductivity and friction and wear properties of Ag@CNTs/Cu composites were studied,and the results showed that the thermal conductivity and friction and wear properties of Ag@CNTs/Cu composites were higher than those of pure copper and CNTs/Cu at a certain volume fraction.,and with the increase of the volume fraction,the thermal conductivity and friction coefficient of the composite material first increase and then decrease.The Ag@CNTs/Cu（0.9vol.%）composite has the best comprehensive performance,the thermal conductivity is 416W/m·k,and the average friction coefficient is 0.51.