Fabrication And Conductive Property Of Silver Coated Bimetal Particles

Silver,as a good conductor of heat and electricity is popular used in many fields.It is well known that silver is too expensive for application,so we can replace it by copper and aluminum because of the similar performance and cheapness.However,copper and aluminum are so active that can be quickly oxidized when exposed to air.The Cu@Ag and Al@Ag core-shell particles are introduced to improve the resistance to oxidation.In this study,the bimetal particles coated by nanostructure silver,such as Cu@Ag and Al@Ag core-shell particles,are controllably synthesized by using simple chemical reduction method.The morphologies and structures of the products are characterized by SEM,TEM,XRD,when the properties are measured by TG and four-point probe.The Cu@Ag core-shell particles synthesized with EG as reducing agent are completely covered with Ag nanoparticles on surface,and showed good conductive ability.The electric resistance of its compacted film is 1.6?/? Meanwhile the Cu-Ag compound particles synthesized with VC as reducing agent are proved to be bimetal particles instead of core-shell structure,which also perform good conductivity and thermal stability,and its electric resistance is as low as 0.74?/?.Al@Ag particles can be achieved without complicated reactivation,whose electric resistance is 30?/?.Differ from the oxidation of the A1 particles,the AI@Ag particles remain the electric conductivity when exposed to air.It lays the foundation of AI@Ag core-shell particles for being used as conductive materials.Silver paste is widely used in resistance heating field due to its high conductivity.The silver paste mixed with Cu@Ag core-shell particles and Ag is used to prepare a kind of flexible heating film by screen printing method.The surface temperature of the films can be increased in low-temperature environment when the voltage is as low as 5V.The results show that when the lines lay along the long dimension of the substrate,the heating efficiency is better.The resistance heating films are applied on the back of one LCD device,where the surface average temperature of the device is increased to above 30? when the environment temperature is as low as 0?.The results lay the foundation of the application of bimetal particles for flexible printing electronics.