Immersion gold plating is a special electroplating process that uses an electrolyte containing gold salt to form a metal film with uniform thickness, high hardness, wear resistance and corrosion resistance on the surface of the substrate. Immersion gold electroplating is a chemical deposition method that generates a layer of coating through a chemical oxidation-reduction reaction. It is generally thicker. It is a type of electroless nickel gold layer deposition method that can achieve a thicker gold layer. Gold plating uses the principle of electrolysis, also called electroplating. In actual product applications, 90% of gold plates are immersed gold plates, because the poor weldability of gold-plated plates is its fatal shortcoming, and it is also the direct reason why many companies abandon the gold plating process. The immersion gold process deposits a nickel-gold coating with stable color, good brightness, smooth coating and good solderability on the surface of printed circuits.