Effects Of Rare Earth On The Process And Performance Of Silver-coated Copper Power And Electrode Coating

The effects of Rare Earth on the process and performance of Silver-coated copper powder and electrode coating were studied. The rare earth elements were added into the activation and plating solution, which have effects on deposition rate, coating rate and structure and micro-morphology. The electrochemical characteristic, conductivity, oxidation resistance and corrosion resistance were determinated. Through the role of rare earth elements, co-deposition mechanism, the influence on the surface of degree clad, the mechanism of action and its influence mode on the process, structure were investigated. Meanwhile, the preparation of the electrode coating and performance test results were explored.The results showed that the effects of rare earth elements on the deposition rate and coating rate and micro-morphology had been changed in different degree. The rare earth elements were added into activation solution, though its catalytic adsorption metal surface, reducing the system's energy, making Pd nuclei generated quickly, restoring fast, losing electronics easily,accelerating the rate of palladium ions reduction, expanding the catalytic center. After the rare earth elements added into bath solution, rest potential and polarizability and cathodic over-potential were improved. The resistivity of coating became decreasing and antioxidant properties had also been improved. Appropriate proportion rare earth elements make crystal grains thin and the structure homogeneous.Therefore,it reduced the corrosion rate in the electrolyte of coating, decreased coating in aqueous solution of current density, obviously improved coating corrosion resistance. The dielectric properties of ceramic capacitors for silver electrode, silver-coated copper powder and copper electrode paste were studied. From the experimental data, we obtained that under the protective atmosphere capacitance of silver-coated copper powder electrode paste prepared by ceramic capacitor is higher than silver electrode paste electrode, dielectric loss is also lower than silver electrode paste. Compared to the standard values, the capacitance and dielectric loss of copper electrode paste were large difference, poor effective, needed to make improvement upon technology and process.