Silicon carbide

Due to its stable chemical properties, high thermal conductivity, low coefficient of thermal expansion and good wear resistance, silicon carbide from silicon carbide manufacturers has many other uses besides being used as abrasive. For example, coating silicon carbide powder on the inner wall of water turbine impeller or cylinder block with special process can improve its wear resistance and prolong its service life by 1 ~ 2 times; The high-grade refractory made of it has the advantages of heat shock resistance, small volume, light weight, high strength and good energy-saving effect. Low grade silicon carbide (containing about 85% SiC) is an excellent deoxidizer. It can speed up steelmaking, control chemical composition and improve steel quality. In addition, silicon carbide is also widely used to make silicon carbide rods for electric heating elements. Silicon carbide has a great hardness, with a Mohs hardness of 9.5, second only to the hardest diamond naturally formed in the world (Grade 10). It has excellent thermal conductivity. It is a semiconductor and can resist oxidation at high temperature. Silicon carbide has at least 70 crystalline forms. α- Silicon carbide is one of the most common isomorphic and heterocrystalline substances, which is formed at a high temperature higher than 2000 ° C and has hexagonal crystalline structure (like wurtzite). β- Silicon carbide, cubic crystal structure, similar to diamond, is generated at lower than 2000 ° C. The structure is shown in the attached figure on the page. Although in the application of heterogeneous catalyst support, it has more advantages than α The type is attractive for its higher unit surface area, but up to now, this type has not been commercially applied. Due to its specific gravity of 3.2g/cm and high sublimation temperature (about 2700 ° C), silicon carbide is very suitable as a raw material for bearings or high-temperature furnaces. It will not melt under any pressure that can be reached, and it has quite low chemical activity. Due to its high thermal conductivity, high collapse electric field strength and high maximum current density, many people try to use it to replace silicon in the application of semiconductor high-power components [1]. In addition, it has a strong coupling effect with microwave radiation and all its high Shenghua points, so that it can be applied to heating metals. Pure silicon carbide is colorless, while industrial brown to black is due to impurities containing iron. The rainbow like luster on the crystal is due to the silica protective layer on its surface.