Silicon Carbide

exceedingly hard, synthetically produced crystalline compound of silicon and carbon. Its chemical formula is SiC. Since the late 19th century silicon carbide has been an important material for sandpapers, grinding wheels, and cutting tools. More recently, it has found application in refractory linings and heating elements for industrial furnaces, in wear-resistant parts for pumps and rocket engines, and in semiconducting substrates for light-emitting diodes.



Silicon carbide was discovered by the American inventor Edward G. Acheson in 1891. While attempting to produce artificial diamonds, Acheson heated a mixture of clay and powdered coke in an iron bowl, with the bowl and an ordinary carbon arc-light serving as the electrodes. He found bright green crystals attached to the carbon electrode and thought that he had prepared some new compound of carbon and alumina from the clay. He called the new compound Carborundum because the natural mineral form of alumina is called corundum. Finding that the crystals approximated the hardness of diamond and immediately realizing the significance of his discovery, Acheson applied for a U.S. patent. His early product initially was offered for the polishing of gems and sold at a price comparable with natural diamond dust. The new compound, which was obtainable from cheap raw materials and in good yields, soon became an important industrial abrasive.

About the same time Acheson made his discovery, Henri Moissan in France produced a similar compound from a mixture of quartz and carbon; but in a publication of 1903, Moissan ascribed the original discovery to Acheson. Some natural silicon carbide was found in Arizona in the Canyon Diablo meteorite and bears the mineralogical name moissanite.