Novel Dendritic Silver-coated Copper Powders: Preparation, Characterization, and Electromagnetic Shielding Performance

Introduction: Electronic devices with functions of communication have been widely used in various fields such as aerospace, the chemical industry, and artificial intelligence. Besides promoting social development and improving the quality of human life, they may also generate electromagnetic radiation and pose health risks. Materials and Methods: To overcome the above mentioned disadvantages, we focus on the development of a chemical reduction method to prepare micron-sized silver-coated copper powders, and the systematic assessment of its electrical conductivity and electromagnetic shielding performance. By flexibly adjusting the silver content (5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%), the influence of silver plating on the electromagnetic shielding efficiency was thoroughly explored. Results: In comparison with copper powder, dendritic silver-coated copper powder (Ag/BCu) prepared via chemical reduction exhibits drastically enhanced electromagnetic shielding in high-frequency bands (>6 GHz). The maximum Electromagnetic interference (EMI) shielding efficiency (SE) value of a specific Ag/BCu at 8.5 dB could be attributed to the improved conductivity and high-frequency reflectivity. As the mass percent of silver is 20%, the electromagnetic interference shielding effectiveness (EMI SE) reaches 32 dB. Discussion: The electroless chemical plating of silver has shown great potential for highfrequency electromagnetic shielding coatings and composite materials, offering a viable design strategy for the development of novel materials with excellent electromagnetic compatibility. Conclusion: Dendritic silver-coated copper powders with controlled silver contents were successfully prepared via a chemical reduction method. The results confirm that the silver coating significantly enhances the EMI SE, especially at high frequencies.