Fabrication of dendritic silver-coated copper powders by galvanic displacement reaction and their thermal stability against oxidation

• Published in: Applied surface science 2016-12, Vol.389, p.865-873
• Main Authors: Park, Yu-Seon, An, Chang Yong, Kannan, Padmanathan Karthick, Seo, Nary, Zhuo, Kai, Yoo, Tae Kyong, Chung, Chan-Hwa
• Format: Article
• Language: English
• Subjects: Core-shell; Dendritic silver-coated copper powders; Galvanic displacement reaction; Resistivity; Thermal stability
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.08.008

•The dendritic silver-coated copper powders with high specific surface area have been prepared using a simple wet chemical reduction process at room temperature.•It is found that the Cu starts to be oxidized into Cu2O followed by CuO at elevated temperatures.•The more amount of Ag-coating provides the less oxidation, which confirms that the Ag-shell prevents the Cu-core from oxidation.•The resistivity of dendritic 33.27wt.% Ag-coated Cu powders was measured to 25.67μΩcm after the annealing at 150°C for 30min. Two steps of wet chemical processes have been developed for the preparation of core-shell nanostructures of copper and silver, which is a facile and low cost method for the production of large quantity of dendritic powders. First step involves a galvanic displacement reaction with hydrogen evolution which is the motive force of spontaneous electrochemical reaction. To achieve the core-shell structure, silver has been coated on the dendritic copper using the galvanic displacement reaction. The dendritic silver-coated copper powders exhibit high surface-area, excellent conductivity, and good oxidation resistance. It has been found that silver-coated copper powders maintain the electrical conductivity even after annealing at 150°C for several to tens of minutes, thus it is a promising material and an alternative to pure silver powders in printed electronics application.