Silicon Carbide (chemical formula SiC), also known as emery or refractory sand, is a widely used inorganic compound in modern industry. Because natural silicon carbide is extremely rare, almost all SiC products on the market are artificially synthesized, mainly divided into black silicon carbide and green silicon carbide, which are widely used in abrasives, refractories, metallurgical deoxidation, semiconductors and other fields.
Silicon carbide of different particle sizes has clear standards for chemical composition, mainly including SiC, free carbon C and ferric oxide Fe₂O₃. The following are the chemical composition indicators of common particle sizes.
| Particle Size Range | SiC(%) | C(%) | Fe₂O₃(%) |
| 12#–19# | 98.5 | 0.2 | 0.6 |
| 100#–180# | 98 | 0.3 | 0.8 |
| 220#–240# | 97 | 0.3 | 1.2 |
Another group of common particle sizes and chemical compositions is as follows:
| Particle Size Range | SiC(%) | C(%) | Fe₂O₃(%) |
| 20#–90# | 99 | 0.2 | 0.2 |
| 80#–100# | 98.5 | 0.25 | 0.2 |
| 220#–240# | 97.5 | 0.25 | 0.7 |
| W63–W20 | 97 | 0.3 | 0.7 |
| W14–W10 | 95.5 | 0.3 | 0.7 |
| W7–W5 | 94 | 0.3 | 0.7 |
Black silicon carbide is produced by the reduction reaction of quartz sand and coke powder at high temperatures. Its Mohs hardness is 9.2–9.5, and microhardness is about 3300Kg/cm³. With SiC content above 95%, it has high toughness and strength, and is mostly used for processing cast iron, glass, ceramics, stone, refractories and other materials with low tensile strength.
Black silicon carbide also features high mechanical strength, stable chemical properties, high thermal conductivity, low thermal expansion coefficient and good wear resistance, together with certain electrical and thermal conductivity, making it cost-effective and widely applied.
Green silicon carbide is synthesized from quartz sand, petroleum coke and sodium chloride at temperatures above 2000℃, appearing as green translucent crystals. Its microhardness ranges from 3280 to 3400 kg/cm³. With higher purity and hardness, it is mainly used for processing cemented carbide, titanium alloy, high-speed steel and other precision materials.
Green silicon carbide is suitable for bonded abrasives, coated abrasives, free grinding and polishing, and enjoys growing demand in precision tools, advanced ceramics and optical processing.
Industrial silicon carbide is mainly produced in electric resistance furnaces. Using quartz and petroleum coke as main raw materials, they are crushed, ground, batched and fed into the furnace. When the core temperature reaches 2500℃–2700℃ and charge temperature reaches about 1450℃, raw materials react to form silicon carbide and release carbon monoxide.
Sawdust is usually added to improve air permeability during smelting, and salt is needed for green silicon carbide production. Some SiC may decompose briefly at ultra-high temperature, but silicon will recombine with carbon to form stable silicon carbide crystals.
In 2026, the silicon carbide industry has expanded far beyond traditional abrasives and refractories. It is booming in third-generation semiconductors, new energy vehicles, photovoltaic and energy storage systems. Continuous breakthroughs have been made in large-size SiC substrates, with 8-inch substrates gradually entering mass production, further reducing device costs.
The 800V high-voltage platform for new energy vehicles is becoming mainstream, and SiC power devices are increasingly used in motor controllers, OBCs and DC/DC converters, greatly improving driving range and shortening charging time. SiC solutions are also widely adopted in PV inverters and energy storage converters to enhance conversion efficiency and heat dissipation.
In metallurgy, silicon carbide is widely used as a steelmaking deoxidizer for silicon enhancement, carbon increase and deoxidation. It features high specific gravity, easy absorption, low dust, low phosphorus and low sulfur, helping improve molten steel purity and steel quality.
At present, silicon carbide products have a complete range of forms including blocks, granules, micropowder and ultra-fine powder, meeting GB, FEPA, JIS and other international standards, and exported to many countries and regions as an essential basic material for global manufacturing.