Preparation and properties of copper-silver core-shell powder composite conductive paste

In this study, copper-silver core-shell powder with a uniform and dense silver layer was prepared by electroless plating, and the effects of powder content, sintering temperature, and holding time on the properties of conductive slurry were systematically investigated, respectively. Firstly, the electrical conductivity of the paste improved significantly as the copper-silver core-shell powder content increased from 65% to 85%. However, the conductivity improved stably once a certain threshold was reached. Secondly, optimization of the sintering temperatures showed that 700 ℃ was the optimum one. The paste had the lowest square resistance at this temperature yet the best surface morphology. However, excessive sintering temperatures resulted in abnormal grain growth of the powder, negatively affecting the density of the conductive network. Finally, optimization of the holding time showed that 15 minutes provided the best curing effect, making the paste the lowest resistivity and the densest conductive network. The results of this research provided a technical approach and theoretical basis for the preparation of high-performance, low-cost conductive pastes.