Why metal sealing rings are plated by silver coating: A molecular dynamics perspective

Silver (Ag) coatings are widely applied on metal sealing rings to enhance performance under extreme service conditions. This study employs molecular dynamics (MD) simulations to comparatively investigate the microscopic contact and wear behavior between silver-coated and uncoated iron (Fe) substrate. Results show that the Ag coating increases the real contact area by 309 %, reduces the wear rate by 16.5 %, and decreases tangential friction force by 44.4 %. These improvements are mainly attributed to the low shear strength and high ductility of Ag coating, as well as the barrier effect of the Ag-Fe interface. Comparative simulations with other representative coatings such as Au and Ni confirm the superior performance of Ag coating. This research elucidates key atomic-scale mechanisms by which Ag coating enhances the sealing and tribological performance of metal substrate, providing a theoretical foundation for its optimized design and application.