Some metals are chromium plated to make them look more attractive and to prevent them from corroding or rusting. Chromium is a silver white, hard, brittle metal which was discovered in 1798 by N.L. Vauquelin. Its non-corrosive, high strength, heat resistant characteristics are utilized in alloys and as an electroplated coating. In electroplating, the article to be plated is connected to the negative terminal of a battery and placed in a solution known as electrolyte. Direct electric current is introduced through the anode or positive terminal, which usually consists of the metal with which the article is to be coated. Metal dissolves from the anode and forms a deposit on the article. The electrolyte for chromium contains chromic acid and sulphuric acid.
It deposits a bright top layer but this is not the most important part of the electro plating. The chromium is only about 0.0002 inches thick. Under it lies a thick layer of nickle and beneath that again may be a layer of copper. Many household appliances are chromium plated and so are the bright parts of an automobile. Tools, chemical equipment, electric appliances, gears, packing machinery and hundreds of other articles are similarly treated to give them brightness , beauty or resistance to wear and rust. Electro plated and polished chromium is bright bluish white with a reflecting power which is 77 per cent that of silver.