Plating is the technique of applying a thin layer of a more expensive metal over a less-expensive base metal. This is achieved with the application of an electric current. There are a number of reasons why plating is useful in production, and the process has many industrial applications from the plating of small electronic parts to the plating of aerospace equipment.
Plating is used for inhibiting corrosion, surface protection, decoration, altering conductivity, radiation shielding, and more. Iron is often plated with nickel to resist rust; base metals are plated with gold or silver to enhance the appearance of jewelry or collectible items; tinplate is used in the manufacture of tin cans for food storage.
The plating process requires thorough cleansing of the base metal, first with an alkaline solution, then with an acid solution, followed by rinsing in water. A negative charge is applied to the base metal via a connection to the negative pole of a battery or other power supply, and the item is immersed in a metallic salt solution of the metal with which it is to be coated. This solution has a positive charge. The positively charged metallic ions are attracted to the negatively charged base metal, resulting in a chemical reaction that creates a metallic coating on the base metal.
More information on plating can be found at Business.com.