Electroplating, sometimes called electrodeposition, is the process by which an electric current, provided by an external supply of direct current such as a battery, is passed through a solution resulting in the chemical breakdown of this electrolyte. This results in metal being transferred from one electrode—the anode— via metal ions in the solution, to the other—the cathode—which has the effect of the target object being coated with a thin layer of the metal that had formed the anode.
The Italian chemist Luigi Brugnatelli (1761-1818) is credited with inventing electroplating in 1805. He used Alessandro Volta's earlier invention of a battery, the voltaic pile, to facilitate the first electrodeposition.
Electroplating is used in many industries for decorative as well as functional purposes. It can increase the value or improve the appearance of an object. For example, jewelry is often gold-plated, and silverware may be made of cheaper metal coated with silver. The technique is also used to silver-plate table cutlery. Coatings such as zinc and tin also provide protection against corrosion and certain objects, such as steel car burnpers, are weatherproofed by being electroplated with first nickel and then chromium. Hard chromium is used to decrease frictional wear in moving machinery by electroplating the surfaces of hydraulic pistons and camshaft-bearing diameters.
Electroplating is also used to silver-plate copper or brass electrical connectors, because silver tarnishes much more slowly and has a higher conductivity than those metals, resulting in more efficient electrical connections. Similarly, connectors used in computers and other electronic devices may be plated with gold or palladium over a barrier layer of nickel to improve electrical conduction.
