Electroplating is generally carried out in order to improve the
appearance or corrosion resistance of the surface of a metal by
electrodepositing a thin layer of metal ion on it. The metal substrate
to be coated is made by the cathode in an electrolytic cell. The cell
used in electroplating contains an electrolyte which is usually an
aqueous solution containing a reasonably high concentration of an ion
of the metal which is to be electroplated on the surface. The cell
anode is usually a piece of the metal to be plated from solution; this
enables the anode reaction of metal dissolution to replace the metal
ion lost from solution by the cathodic decomposition.