Electroplating

The deposition of a thin gold layer or coating onto a conducting substrate, typically a base metal, by electrolysis, usually from a gold potassium cyanide electrolyte.
Electroplating is widely used in the electronics industry to coat contact points but also has many decorative applications in the plating of costume jewellery, watches, cigarette lighters and pens. It is also used in aerospace, where a thinly deposited layer of gold reflects heat from jet or rocket engines. The gold plating is often as thin as one thousandth of a millimetre.