| In electronic industry, Sn-Pb solderring alloy is used as electronic packaging material. But Sn-Pb soldering is harmful to human because of the existed Pb. Many countries in the world have made policies to restrict the use of substance containing Pb. So investigation of new material to substitute the Sn-Pb soldering is helpful. Conductive resin has the similar performance as Sn-Pb soldering. And the epoxy conductive resin is friendly to human. Now most epoxy resinsare filled with silver powders, which are expensive. Although copper has the similar electric resistivity with silver, it is easy to be oxidized in atmosphere. In this work, different morphologies of coppers are prep ared and are coated with silver to insure them stable. And the coated powders are used as fillers in epoxy resin.Envirmental friendly chemical agents of vitaminC(Vc) as reducing agent and β-cyclodextrins as protective agent were used to prepare monodisperse copper and coated copper nanoparticles. The influences of adding sequence, concentration of Vc, reacting temperature and pH on copper were disscussed. Ammonia as complexing agentis used to combine with copper ions to prepare micron scale spherical copper particles. Different Ag/Cu ratio affects the coating layer outside the copper. And the prepared particles were characterized by XRD, TEM, XPS, FT-IR, TG-DTA. Results show that copper particles were coated with dense silver shells. And TG-DTA reveals the coated copper particles have better oxidation-resistance.Flake copper particles were prepared with PEG800as template agent. Effects of PEG800volume concentration and reacting temperature on flake coppers were studied. And effect of PEG800in forming flake copper was analysised. The copper crystal has a (111) preferential orientation. The best conditionsfor preparing flake coppers were CPEG800=90ml/L, T=80℃, CCusO4·5H2O=0.2mol/L, CNaH2O·2H2O=0.14mol/L. Silver coated flake copper were prepared by replacement. And the influence of Ag/Cu on composite was discussed. Also composite powders were characterized and TG-DTA revealed their higher oxidation resistance.Copper nanowires were synthetized with quadrol, hydrazine and sodiumhydrate. The quadrol guided the orignal reduced copper nanoparticles to growth into nanowire. Effect of concentration of quadrol, concentration of sodiumhydrate, reacting temperature and stir speed on copper nanowire growth were studied. Better copper nanowires can be obtained by following conditions:quadrol concentration of17.5ml/L, hydrazine concentration of17.5M, reacting temperature of60℃. Influence of different Ag/Cu ratio on coated copper nanowire was studied. The coated copper nanowire was characterized. Results show that the Cu nanowires havea heavy loss at the Ag/Cu>1, because the nanowire has a high specific surface and a rapid replace reaction rate with silver. TG-DTA revealed that resistance to oxygen for silver coated copper nanowire has been improved greatly.Epoxy is used as matrix to prepare conductive adhesive. First, viscosity of epoxy is diluted with different epoxy/acetone mass ratio. As epoxy/acetone mass ratio is6:4, the adhesive has a proper viscosity of15.11mPa-s, which is suited for preparing conductive adhesive. The different morphologies of particles are used as fillers in epoxy matrix. Specific resistance and shear strength of epoxy resin were tested. Results show the spherical particles have a higher specific resistance than flake particles. Coated copper has lower resistance than uncoated copper. The volum resistivity is decrease with the increase of volume fractions of particles. The conductivity for adhesive with flake particles as fillers is higher because there are more contacts sites than spherical particles do. The conductivity of coated copper is higher than that of pure copper because core-shell structure affects electronic distribution. Further more, the addition of nanoparticles can't improve the conductivity of epoxy resin, because the added nanoparticles increase the thickness between the particles, which is equivalent to increase contact resistance.
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