what is silicon carbide used for
Silicon carbide is also known as carborundum or refractory sand. At present, China's industrial production of silicon carbide is divided into 2 types: black silicon carbide and green silicon carbide, both of which are hexagonal crystals with a specific gravity of 3.20 to 3.25.
Black silicon carbide is made of quartz sand, petroleum coke and high-quality silica as main raw materials, and is smelted by electric furnace at high temperature. Its hardness is between corundum and diamond, the mechanical strength is higher than corundum, brittle and sharp. Green silicon carbide is made of petroleum coke and high-quality silica as the main raw material, adding salt as an additive and smelting by electric furnace at high temperature. Its hardness is between corundum and diamond, and its mechanical strength is higher than that of corundum. Commonly used silicon carbide abrasives have two different crystals, one is green silicon carbide, containing more than 97% SiC, mainly used for grinding hard gold-containing tools. The other is black silicon carbide, which has metallic luster, contains more than 95% SiC, and has higher strength than green silicon carbide, but has lower hardness. It is mainly used for grinding cast iron and non-metal materials.
Silicon carbide application also includes: silicon carbide contains both silicon and carbon, and is an element that can react actively with oxygen. Therefore, silicon carbide can be used as a metallurgical deoxidizer. In the field of casting, carbon can help increase the carbon content of the casting.
Silicon carbide has a high melting point and a small coefficient of thermal expansion, and can also be used as a high temperature resistant material.