Preparation Of CNTs/Ag Composite Powder And Its Composite Material Prepared By Molecular-level Blending Method

In recent years,nano-materials reinforced silver-based composite materials have developed rapidly.Generally,composite materials are prepared by different preparation methods to make the nanophase uniformly or in a certain direction distributed in the silver matrix.Among them,composite material which adding carbon nanotubes(CNTs)as a reinforcing phase to the silver matrix is a material with excellent performance.In this study,CNTs/Ag₂O composite powder was prepared by molecular level mixing method,and CNTs/Ag composite material was prepared by SPS sintering.Firstly,it starts with the preparation process of CNTs/Ag₂O composite powder,and its influence on the properties of composite powder were studied;secondly,the reduction method of CNTs/Ag₂O composite powder were studied;finally,the influence of the sintering process,the content of carbon nanotubes and different way to adding carbon nanotubes on the composite material were studied,and the electrical conduction mechanism of the CNTs/Ag composite material was further analyzed.The main conclusions are as follows:(1)CNTs/Ag₂O composite powder was prepared by molecular level mixing method.When the concentrations of NH₃·H₂O,Ag NO3,and Na OH were 0.1M,0.1M,and 2M,the reaction temperature was 25?,and the reaction stirring rate was 600r/min,CNTs/Ag2O composite powders with uniform carbon nanotube dispersion,regular silver oxide morphology,and good combination of carbon nanotubes and silver oxide can be prepared.(2)The flake-shaped CNTs-Ag₂O/Ag composite powder was prepared by one-step ball milling method,and the CNTs/Ag composite powder was obtained by hydrogen reduction.(3)The effects of sintering process,content of carbon nanotubes and different way to adding carbon nanotubes on composite materials were studied.When the sintering temperature is 1023K and the content of CNTs is 0.75wt%,the hardness can be increased by 68.67%compared with pure silver.When the CNTs are plated with nickel later,the hardness can be further increased to 100.3HV.(4)The conduction mechanism of the CNTs/Ag composite material was further analyzed,and the theoretical conductivity model of the composite material was obtained.It was found that after CNTs was plated with nickel,the probability of elastic scattering at the interface was increased,thereby improving the conductivity of the composite material,and combined with the model,a method to improve the conductivity of the composite material is speculated.