Silicon

Element, chemical symbol Si. Silicon, one of the most abundant elements on earth and a powerful de-oxidizing agent, is a major portion of silica and silicates (rocks, quartz, sand and clay). Its inclusion improves the physical properties of steel. Combined with manganese, it is used in materials for springs of various types and gives best service in this capacity when combined with a carbon content of from 0.45 to 0.70 percent. A silicon content generally limited to 4 percent is used for electric resistance wires as it increases electrical resistance. Also used as an alloying element with copper and aluminum.