Due to its stable chemical properties, high thermal conductivity, low thermal expansion coefficient, and good wear resistance, silicon carbide has many other applications besides abrasives, such as coating silicon carbide powder on turbine impellers cylinder blocks by unique processes. The inner wall can improve the wear resistance and prolong the service life by 1~2 times; the advanced refractory material used for the manufacture is heat-resistant, small in volume, light in weight, high in strength, and has an excellent energy-saving effect. Low-grade silicon carbide (about 85% SiC) is a superb deoxidizer, which speeds up steelmaking and facilitates control of steel’s chemical composition and quality. Also, silicon carbide is widely used to make silicon carbide rods for electric heating elements.
Silicon carbide has a high hardness and a Mohs hardness of 9.5, second only to the world’s hardest diamond (10 grade). It has excellent thermal conductivity and is a kind of semiconductor. It can resist oxidation at high temperatures.
There are at least 70 crystal forms of silicon carbide. Alpha-silicon carbide is the most common isomorphous substance formed at high temperatures above 2000 °C and has a hexagonal crystal structure (like wurtzite). —SiC, cubic system, similar to diamonds, is produced below 2000 °C; the design is shown in the figure on the page. Although in the application of the heterogeneous catalyst carrier, it has a higher unit surface area than the α type, and another silicon carbide, μ-silicon carbide, is the most stable and has a more pleasant sound when colliding. But until today, these two types have not yet been applied commercially.