Rare metals often need to be plated on board edge connectors, protruding contacts or gold fingers to provide lower contact resistance and higher wear resistance. This technology is called finger plating or protruding part plating. Gold is often plated on the protruding contacts of nickel plated plate edge connectors. The protruding parts of the gold finger or plate edge are manually or automatically plated. Currently, the gold plating on the contact plug or gold finger has been replaced by plating, lead plating, and button plating. The process is as follows:

　　1) Peel off the coating to remove tin or tin lead coating from protruding contacts

　　2) Rinse with cleaning water

　　3) Scrub with abrasive

　　4) Activated diffusion in 10% sulfuric acid

　　5) Nickel plating thickness on protruding contacts is 4-5 μ M

　　6) Cleaning to remove mineral water

　　7) Gold permeation solution treatment

　　8) Gilding

　　9) Cleaning

　　10) Drying