Silicon Carbide - Discovery and Early Production

Discovery and Early Production

Non-systematic, less-recognized, and often unverified syntheses of silicon carbide were reported early, J. J. Berzelius's reduction of potassium fluorosilicate by potassium (1810); Charles Mansuète Despretz's (1792–1863) passing an electric current through a carbon rod embedded in sand (1849); Robert Sydney Marsden's (1856–1919) dissolution of silica in molten silver in a graphite crucible (1881); Albert Colson's heating of silicon under a stream of ethylene (1882); and Paul Schuetzenberger's heating of a mixture of silicon and silica in a graphite crucible (1881). Nevertheless, wide-scale production is credited to Edward Goodrich Acheson in 1890. Acheson was attempting to prepare artificial diamonds when he heated a mixture of clay (aluminum silicate) and powdered coke (carbon) in an iron bowl. He called the blue crystals that formed Carborundum, believing it to be a new compound of carbon and aluminum, similar to corundum. In 1893, Henri Moissan discovered the very rare naturally-occurring SiC mineral while examining rock samples found in the Canyon Diablo meteorite in Arizona. The mineral was named moissanite in his honor. Moissan also synthesized SiC by several routes, including: the dissolution of carbon in molten silicon; melting a mixture of calcium carbide and silica; and by reducing silica with carbon in an electric furnace. However, Moissan ascribed the original discovery of SiC to Acheson in 1903.

Acheson patented the method for making silicon carbide powder on February 28, 1893. Acheson also developed the electric batch furnace by which SiC is still made today and formed The Carborundum Company to manufacture bulk SiC, initially for use as an abrasive. In 1900 the company settled with the Electric Smelting and Aluminum Company when a judge's decision gave "priority broadly" to its founders "for reducing ores and other substances by the incandescent method". It is said that Acheson was trying to dissolve carbon in molten corundum (alumina) and discovered the presence of hard, blue-black crystals which he believed to be a compound of carbon and corundum: hence carborundum. It may be that he named the material "carborundum" by analogy to corundum, which is another very hard substance (9 on the Mohs scale).

The first use of SiC was as an abrasive. This was followed by electronic applications. In the beginning of the 20th century, silicon carbide was used as a detector in the first radios, and in 1907 Henry Joseph Round produced the first LED by applying a voltage to a SiC crystal and observing yellow, green and orange emission at the cathode. Those experiments were later repeated by O. V. Losev in the Soviet Union in 1923.