Silicon Carbide is a kind of a-SiC with shape of hexagonal crystal. In today's world, silicon carbide as the most widely used and one of the most economic material, can be called corundum or refractory sand. At present, China produces two types of silicon carbide, green color and black color. Microhardness: 2840～3320 kg/ mm2, its mohs hardness is a little lower than diamond, it is 9.5. However it enjoys the high thermal conductivity, stable chemical performance, small thermal expansion coefficient, good wear resistance.