Electroplating – a metal in its ionic form is induced with electrons to a non-ionic coating.
Most common involves:
Chemical which contains the ionic form of required coating metal, anode ( charged) which may consist of metal to be plated (soluble anode) or insoluble anode (platinum, titanium, typically carbon, lead, steel), and a cathode ( – charged) where electrons induced to form a film of non-ionic metal.
Gold plating envolves depositing a layer of gold on surface of metal, often copper or silver.
Gold plating is used in electronics, and provides a corrosion-resistant conductive layer on copper, in electrical connectors or circuit boards.
gold-on-copper, copper atoms have a tendency to diffuse through gold layer, reslting in tarnishing of surface and an oxide/sulfide layer.
A layer of barrier, usually nickel, has to be placed on the copper, forming copper-nickel-gold layers.