Electroplating

Electroplating is the process of using electrodeposition to coat an object in a layer of metal(s). Engineers use controlled electrolysis to transfer the desired metal coating from an anode (a part containing the metal that will be used as the plating) to a cathode (the part to be plated).

Diagram of copper electroplating using an electrolyte bath of copper sulfate, sulfuric acid, and chloride ions. (image source)

The anode and cathode are placed in an electrolyte chemical bath and exposed to a continuous electrical charge. Electricity causes negatively charged ions (anions) to move to the anode and positively charged ions (cations) to transfer to the cathode, covering or plating the desired part in an even metal coating. Electroplating takes a substrate material (often a lighter and/or lower-cost material) and encapsulates the substrate in a thin shell of metal, such as nickel or copper.