Recent Progress in the Manufacture and Performance of Silver-Based Conductive Coatings for Electrical Contacts: A Review

Silver (Ag)-based conductive coatings are widely used in electrical contacts due to their excellent electrical conductivity, low contact resistance, good thermal stability and oxidation resistance, although their susceptibility to sulfidation and environmental corrosion is a concern under certain service conditions. In recent years, significant progress has been achieved in both the manufacture and performance optimization of Ag-based coatings to satisfy the demanding requirements of modern electrical and electronic systems. This review summarizes recent advances in fabrication techniques and processing parameters for Ag-based coatings, including electroplating, electroless deposition, magnetron sputtering, electrospark deposition, thermal spraying, and electrical explosion spraying on metallic substrates, particularly on copper and steel substrates. More attention is given to microstructural design strategies, such as the incorporation and homogeneous dispersion of reinforcement or solid lubricant phases within the Ag matrix, to enhance contact reliability and operational endurance. The performance of Ag-based coatings is analyzed in terms of their physical, chemical and mechanical properties, electrical contact resistance, friction and wear behavior, arc erosion resistance, and environmental durability under different service conditions. Key challenges, including coating degradation under high electrical loads, mechanical wear, and corrosive environments, are highlighted. Future research directions are outlined, focusing on multifunctional coating structures that enhance surface performance and ensure the long-term durability of electrical contacts.