Study On Preparation And Properties Of Silver Coated Copper Conductive Adhesive System

With the rapid development of the domestic electronics industry, the soldering process has been unable to meet the current requirements of the electronics industry thin layer,conductive adhesive for their most important alternatives has got rapid development.However, the domestic high.performance mainly silver conductive adhesive, this kind of conductive adhesive is high cost, and the silver migration occurred at high temperature that will affect the conductivity of conductive adhesive. In this paper, taking copper as the basis for the preparation of silver coated copper in situ reduction, taken it as filler, and prepared modified epoxy resin and improved process of the conductive adhesive curing, then discussed its comprehensive performance. Therefore, this article researched and analysied from the following aspects:First of all, we respectively discussed the ultrasonic conditions, the dosage of reductant and the kinds and dosage of surface active agent on the effect of ultrafine copper powder,which was prepared by solution method. Then analysis of preparation of ultrafine copper powder morphology by SEM, made particle size analysis and dispersion by X.ray diffraction analysis. The results showed that the ultrafine copper powder prepared under the ultrasonic condition, is well dispersion and particle size is uniform; the amount of reducing agent has no influence on the morphology of product, the concentration of c3 is the best;surfactant micelle effect the morphology of product, the particles is grow up on the surface of micelle; if the agglomeration of product particle will ensue, and the phagocytosis growth will occur between the particles and the particles.Secondly, for the preparation of silver coated,copper powder, we discussed that how the reactant concentration, complexing agent and solvent effect on the result of coating. We analysed the morphology, particle size and dispersion of ultra-fine copper powder by scanning electron microscope(SEM); analysis composition of product by X.ray diffraction.The results showed that prepare the silver coated copper in aqueous solution, silver plates on copper surface in the form of dot, the lower the concentration of silver nitrate, the more perfect the concentration of silver nitrate of 15 g/L is the best; the complexing ability of complexing agent EDTA tetrasodium on silver ion is less than NH3 · H2 O, taken NH3 · H2 O as complexing agent the product is better; In different solvents, the morphology is different.Last, after improving epoxy resin, we took the above product as packing to make conductive adhesive and discussed the performance. Epoxy resin and polyurethane proportion is not at the same time, the curing effect is different, the performance of cured coating is different; when the ratio of epoxy resin and polyurethane is 5:1, the conductive adhesive can be completely cured at room temperature, the cured coating has smaller bubble,the comprehensive mechanical properties id best, the adhesion is first level; After mechanical properties and electrical performance test, the conductive adhesive shows that peel strength was: 15.5 MPa; volume resistivity of 0.5×10-4 U·cm.