Carborundum, << `kahr` buh RUHN duhm >> (chemical formula, SiC), is a trade name for silicon carbide, an abrasive. It is prepared from sand and carbon. Carborundum is almost as hard as a diamond, and is one of the most important abrasives used for grinding and cutting hard materials such as steel. Carborundum grains are sometimes pressed together to make grinding wheels. They may also be glued to cloth or paper to make sheets or belts used for polishing, grinding, and sanding. In electronics, resistors known as thermistors are often made of silicon carbide. Carborundum is also used as a furnace lining.
