Coating a metal or other material, such as plastic or china, with a hard, nonporous metallic surface to improve durability and beauty. Early plated goods (old Sheffield plate) are made by the process invented by Thomas Boulsover, and consist of a sandwich of copper between two layers of silver. Today surfaces such as gold, silver, stainless steel, palladium, copper, and nickel are applied by dipping an object into a solution containing the desired surface material, which is deposited by chemical or electrochemical action (see electroplating). Much plating is done for decorative purposes, but still more is done to increase the durability and corrosion resistance of softer materials. Most automotive parts, appliances, housewares and flatware, hardware, plumbing and electronic equipment, wire goods, aircraft and aerospace products, and machine tools are plated for durability. See also galvanizing, terneplate, tinplating.