Electroplating is the process of coating an object with a metal. Electroplating can be done using electrolysis, where the metal object you want to coat is the cathode, and the source of the metal to coat the object is either a metal anode or metal ions in the electrolyte. The positive metal ions will travel from the anode, or electrolyte, to the cathode where the metal ions will be deposited on the cathode surface. The setup of this electrolytic cell is shown in Figure 1.
Here are a few reasons to electroplate an object, each with an example application:
To improve the appearance of an object - e.g. jewelry.
To protect an object from corrosion - e.g. kitchen utensils.
To give certain material properties to an object such as altering the conductivity of the object e.g. parts of electrical circuits in electronic devices.
Figure 1 - An electrolytic cell electroplating a spoon in silver.
There are a few processes that are similar to electroplating - electropolishing, electroforming, and electrotyping. The opposite of electroplating is electropolishing. In this process, metal ions are removed from the surface of an object. This object acts as an anode. Electroforming and electrotyping are similar processes that make metal objects using electrolysis. The difference between these processes is the cathode that they use.