ACHESON, EDWARD GOODRICH

born March 9, 1856, Washington, Pa., U.S. died July 6, 1931, New York, N.Y. American inventor who discovered the abrasive Carborundum and perfected a method for making graphite. Acheson joined inventor Thomas A. Edison's staff in 1880 and helped to develop the incandescent lamp at Edison's laboratories at Menlo Park, N.J. In 1881 he installed the first electric lights for Edison in Italy, Belgium, and France. Upon returning to the United States, Acheson quit Edison and in 1884 began his own experiments on methods for producing artificial diamonds in an electric furnace. He heated a mixture of clay and coke in an iron bowl with a carbon arc light and found some shiny, hexagonal crystals (silicon carbide) attached to the carbon electrode. Because he at first mistakenly thought the crystals were a compound of carbon and alumina from the clay, he devised the trademark Carborundum, after corundum, the mineral composed of fused alumina. In 1893 he received a patent on this highly effective abrasive. Later, while studying the effects of high temperature on Carborundum, he found that the silicon vaporizes at about 4,150 C (7,500 F), leaving behind graphitic carbon. He was granted a patent for this process in 1896. In all, he received 69 patents and organized several firms to commercialize his inventions, including The Carborundum Company, Niagara Falls, N.Y.