Plating is the general name of surface-covering techniques in which a metal is coated onto a solid surface. Plating is indispensable for the manufacture of computers, mobile phones, and electronic devices as well as for surface treatment techniques. Moreover, it is a key technology for the development of new machines. Recently, plating techniques have been done on a smaller scale than the microscopic, so it is appropriate to call them “nanotechnology”.
There are several plating methods. For example, in one method, a solid surface is covered with a metal sheet and then plated by heating. Other plating techniques include vapor deposition under vacuum, sputtering, and methods using vacuum conditions or gas. Recently, however, only plating techniques using a liquid tend to be called "plating".
~Electroplating~ is one of the plating techniques. One electroplating method grows a plating film by melting a positive electrode under an outer electric current source and a soluble positive electrode. Another method uses an insoluble metal, for example, platinum, titanium, stainless steel, or carbon, as the positive electrode, adding a metal for plating as a reagent and then depositing the metal from the reagent. The former method is useful for electrotyping, forming a thick plating film, and making copper sheets by continuous plating. The latter method is useful for plating insoluble metals and noble metals and making functional films by using alloys.
