The Preparation And Performance Of Water-based Conductive Paste Of Carbon Coated Copper

With the rapid development of the global electronic information industry and the enhancement of people's awareness of environmental protection,the demand for high-performance environmental friendly conductive paste is increasing.Based on the research of base metal copper electronic paste,this project prepared by high temperature pyrolysis Cu@C Composite powder was used as conductive reinforcement phase to prepare water-based conductive slurry of copper-clad carbon to improve its conductivity,and green water-based carrier was prepared to replace the traditional organic carrier,so as to reduce the environmental pollution in the sintering process.The process route of carbon coating modification on the surface of ultra-fine copper powder and the influence factors on the conductivity of carbon coated copper composite slurry were studied.(1)In this thesis,polyacrylonitrile carbon rich organic compounds were used as carbon source to coat superfine copper powder,and the copper powder with special shell core structure was prepared Cu@C.The inner layer is copper core,and the outer layer is mainly composed of amorphous amorphous carbon layer,semi graphitized carbon material and some regularly arranged lattice structure,which has a high degree of graphitization.There was a positive correlation.(2)The enhancement of conductivity is studied Cu@C.The effect of the content of composite powder on the conductivity of composite slurry and the mechanism of conductive enhancement were studied.The results show that when the copper powder is mixed with copper powder,the copper powder can be divided into two parts Cu@C When the ratio of composite powder is 92?8(wt%),the conductivity of the water-based conductive slurry is the best,which is 18.76 m ?· cm;compared with pure copper slurry,the resistivity decreases by 48.45%.Cu@C Particles in the slurry can fill the gap between the copper powder particles and form a transverse lap or radial filling with the copper powder,making the formed conductive network more compact and perfect.The conductive carbon layer with regular order of graphite network carbon element lattice structure in the outer layer is equivalent to the "bridge" of current transmission between copper particles,which causes the directional transfer of hot electrons to form tunnel current,and promotes the directional flow of electrons to produce induced current under the effect of emission electric field.(3)The influence of the ratio of each component in the water-based carrier on the printability,film forming and leveling of the composite slurry was studied.The results show that when the ratio of deionized water: CMC: PVP: KH-550: defoamer is 95.9:1.5:1:1.5:0.1,the water-based carrier has stable performance and suitable viscosity at room temperature,and can play a full role in wetting conductive phase,conductive reinforcement phase and adhesive phase.(4)The effects of the content of water binder glass powder and sintering temperature on the conductivity of the composite slurry were studied.Results when the addition ratio of glass powder was 9 wt%,the resistivity of the film was the lowest,which was 10.32 m ?· cm.The results show that the conductivity of the conductive film is the best,and the resistivity is9.73 m ?· cm.