Silicon Carbide (SiC) is an extremely hard and chemically inert material that’s widely used across metallurgy, abrasive wear, refractory and other industries. Furthermore, SiC is also an excellent wide band gap semiconductor and forms naturally as the gemstone moissanite.
Hardness, thermal conductivity and abrasion resistance make alumina an excellent material for use in harsh environments, with doping being an option to alter its electrical properties further.
Characteristics
Silicon carbide (SiC) is an inorganic material with a high melting point and electronic bandgap between 2.4 to 3.3 eV, making it suitable for industrial uses in areas like petrochemical production, mechanical sealing parts, and cutting tools.
Refractory ceramic materials with high thermal conductivity and low thermal expansion rates such as silica are extremely valuable refractory materials, offering great thermal conductivity, low thermal expansion, extreme hardness and durability – features which make silica an extremely beneficial material to work with in refractories. Furthermore, it resists thermal shock well, being capable of withstanding temperatures of up to 1600degC without losing strength or becoming vulnerable.
SiC is an environmentally-friendly material with excellent acid, alkali and molten salt resistance thanks to a protective silica layer forming on its surface. Furthermore, SiC’s Mohs scale rating falls somewhere between that of alumina (9 on the scale) and diamond (10).
Crystalline SiC is made up of hexagonal networks of silicon and carbon atoms bonded together through strong covalent bonds in its crystal lattice structure, giving this material its remarkable strength and toughness. This factor accounts for its exceptional properties.
SiC is found naturally only in very limited amounts in moissanite, and most commercial use today of SiC is synthetically produced. Edward Acheson first synthesized it artificially in 1891 from reacting SiO2 with carbon in an electric furnace to form small black crystals which were ground into powder for use as industrial abrasives.
Applications
Silicon Carbide (SiC) is one of the premier industrial ceramics. This hard, dense and tough material boasts excellent thermal conductivity as well as outstanding mechanical properties for exceptional application requirements. SiC can be customized into different shapes and sizes to meet specific application demands.
SiC is produced industrially by reacting powdered silica with coke in electrical resistance furnaces at high temperatures, producing pure SiC which is colorless. Unfortunately, industrial quantities contain iron impurities which change its appearance to brown to black crystalline solid. Although rarer cases exist as the form of moissanite (green to blue iridescent mineral), all commercial moissanite is synthetically manufactured.
SiC is an extremely hard material that’s resistant to corrosion by water, air, oxygen, nitrogen, phosphorus and organic acids, making it suitable for use as cutting tools, abrasives and grinding wheels as well as serving as the preferred mirror material for many astronomical telescopes. It has excellent heat-resistance. It can withstand extremely high temperatures without shattering and can withstand very high pressure as cutting tools abrasives and grinding wheels are commonly made out of SiC.
SiC is widely utilized within the semiconductor industry for various applications, such as fabricating silicon wafers used to construct electronic devices. Furthermore, SiC makes an excellent material choice for electric vehicle inverters as it can withstand high voltage demands without losing efficiency – meaning electric cars can achieve much greater driving distances while simultaneously decreasing power management system size and weight significantly.
Manufacturing
Silicon carbide’s hardness, rigidity, and thermal stability have long made it an integral component in many modern technologies – from electric vehicles and renewable energy systems to telecom infrastructure and microelectronics – as its unique properties enable it to withstand extreme environments while still remaining functional.
Crystalline silicon carbide has many applications in high-voltage applications, including electric vehicle manufacturing and power conversion inverters. Thanks to the material’s ability to withstand extremely high voltage demands, electric vehicle manufacturers can increase driving distance while decreasing size and weight requirements for inverters. Furthermore, crystalline silicon carbide can also be used in manufacturing semiconductors and power generation plants as a means to lower carbon emissions and build a greener energy economy.
Reaction bonding or sintering are the two primary methods for producing crystalline silicon carbide. Both manufacturing methods produce similar end microstructures, but their methods of formation have an enormous effect on its performance. Reaction bonded crystalline silicon carbide is formed by infiltrating compacts of mixed silicon-carbon powder with liquid silicon before densifying using boron carbide or other sintering aids and sintered at high temperatures.
Sintering of crystalline silicon carbide creates numerous defective slices during its manufacturing process, so device manufacturers should perform defect analysis throughout the production cycle using advanced metrology tools like Scanning Acoustic Microscopy (SAM).
Safety
Silicon carbide is an inhalation irritant and may cause lung damage when exposed in sufficient dose. Repetitive exposure may result in pneumoconiosis, a chronic condition marked by abnormalities on chest x-ray and declining lung function that includes coughing and wheezing; additionally it increases your risk for tuberculosis.
Ceramic was widely used as an industrial abrasive during the late nineteenth and early twentieth centuries due to its higher-than-diamond hardness; it continues to be utilized this way today, but also serves as the foundation for long-lasting ceramic products in multiple industries.
Sintering process used to produce crystalline SiC bonds sub-micron-sized grains of SiC together into dense and durable material. When mixed with alumina it creates an additional tough and resistant ceramic, while when combined with cerium oxide it forms harder but more porous beta SiC material.
American Elements offers crystalline silicon carbide that boasts extremely low impurity levels with a guaranteed Geometrical Dimensional Measurement System (GDMS) percentage of less than 0.02%, making it suitable for demanding applications requiring stable and durable material. To learn more about this specialty product please contact one of American Elements sales representatives.
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