Black silicon carbide is brittle and sharp. It has a good electrical and heat conductivity Knoop hardness is 3100 ~ 3200kg/mm^2. Grinding wheels made of C are suitable for the grinding of metal and nonmetallic materials of low tensile strength such as gray cast iron, brass, aluminum, stone materials, leather and rubber etc.. Moreover, it can also be used in the manufacture of refractory products and electric products etc.