Silicon carbide is known for its stable chemical properties, impressive thermal conductivity, low thermal expansion coefficient, and excellent wear resistance. In addition to its common use as an abrasive, silicon carbide has a variety of other applications. For instance, when silicon carbide powder is applied to the inner walls of hydraulic turbine impellers or cylinder blocks using specialized techniques, it significantly enhances wear resistance and can extend the lifespan of these components by one to two times. Furthermore, it serves as a high-quality refractory material that is lightweight, compact, and strong, contributing to energy savings.
Low-grade silicon carbide, which contains approximately 85% SiC, is an effective deoxidizer that accelerates the steelmaking process, aids in controlling chemical composition, and improves steel quality. Additionally, silicon carbide is extensively utilized in the production of silicon carbide rods for electric heating elements.
With a Mohs hardness of 9.5, silicon carbide ranks just below diamond in terms of hardness. It boasts excellent thermal conductivity, functions as a semiconductor, and is resistant to oxidation at elevated temperatures. There are at least 70 crystalline forms of silicon carbide, with α-silicon carbide being the most prevalent, forming at temperatures above 2000 °C and exhibiting a hexagonal crystal structure. In contrast, β-silicon carbide, which has a cubic structure akin to diamond, forms at lower temperatures. μ-silicon carbide, while less common, is noted for its stability and pleasant sound upon impact, making it suitable for use as a heterogeneous catalytic support due to its higher specific surface area.
With a specific gravity of 3.2 g/cm³ and a high ignition temperature of around 2700 °C, silicon carbide is an ideal raw material for bearings and high-temperature furnaces. It remains solid under achievable pressures and exhibits low chemical reactivity. Its remarkable thermal conductivity, high breakdown electric field strength, and maximum current density have led to interest in its potential to replace silicon in high-power semiconductor applications. Additionally, its strong coupling effect with microwave radiation and high sublimation points make it practical for metal heating applications.
