Silver plating, the plating layer is used to prevent corrosion, increase conductivity, reflectivity and aesthetics. It is widely used in the manufacturing industries of electrical appliances, instruments, meters and lighting appliances. For example, when copper or copper alloy parts are plated with silver, they must be degreasing and rust removed; then pre-plated with thin silver or immersed in a solution of mercury chloride, etc., for amalgamation treatment, so that a Layer a mercury film; then the workpiece is used as a cathode, and a pure silver plate is used as an anode, immersed in a silver potassium cyanide electrolyte prepared by silver nitrate and potassium cyanide for electroplating. Non-cyanide silver plating is also used in electrical appliances, instrumentation and other industries. The electroplating solution uses thiosulfate, sulfite, thiocyanate, ferrocyanide, etc. In order to prevent the discoloration of the silver coating, it is usually subjected to post-plating treatments, mainly immersion, chemical and electrochemical passivation, plating of precious metals or rare metals, or coating of coatings, etc.