Electroplating is the process that consists of applying a thin decorative or protective metal layer on another material. It is a common technique used to improve appearance and durability of metal objects. For example, gold and platinum are applied to jewelries made of cheap materials. The thickness of these layers varies between 0.03 and 0.05 mm.
The composition of electrolyte bath varies and it is kept secret often, but usually it depends on metal to be deposited, and it may affect the durability and surface quality. For example, the silver deposited from a solution of silver nitrate does not stick very well to a metallic surface.
Nickel can be used as a protective layer and it is coated from a solution of nickel sulphate.
Chrome is plated from a H2CrO4 solution.
Some monomers (styrene) are easily used to create organic anions. These anions can polymerize in a process called anionic polymerization. We can use an electrical circuit to start this process, the polymer being located to the cathode. This process was used to paint new cars. This process has the advantage that it takes place in water and it is no need to spray with volatile organic solvents.