Silicon Carbide Ceramics

Silicon carbide ceramics (SiC) is an advanced ceramic that combines the characteristics of traditional ceramics and new materials. Its performance and application fields are extremely wide.

Physical and chemical properties:

• High hardness: Mohs hardness reaches 9.5, second only to diamond and cubic boron nitride.
• High temperature strength: It can still maintain high strength at 1600°C or even higher, and is one of the best high temperature performance materials among known ceramics.
• Corrosion resistance: Silicon carbide ceramics have strong resistance to corrosive media such as acids, alkalis, and salts, and excellent chemical stability.
• Thermal properties: Low thermal expansion coefficient, high thermal conductivity (better than most metals), and outstanding thermal shock resistance.
• Electrical properties: It is a semiconductor material, and its conductivity decreases with increasing temperature.

 

Structural characteristics:

SiC crystals are based on tetrahedral structures, and there are many variants (such as α-SiC and β-SiC), among which α-SiC contains polymorphs such as 4H and 6H, and β-SiC is a cubic crystal system.

Synthesis method of silicon carbide ceramics

• Traditional synthesis: High-temperature reduction reaction of quartz sand (SiO₂) and coke (SiO₂ + 3C → SiC + 2CO).
• Modern processes: Including sol-gel method, hydrothermal method, electric spark sintering method, as well as reaction sintering, hot pressing sintering, gel injection molding, etc. For example, foam ceramics are prepared by adding additives such as magnesium oxide and using polyacrylamide as an additive.

3D printing technology

In view of the problems of complex and high cost of traditional processes, 3D printing can achieve rapid prototyping of complex shapes, reduce costs and shorten cycles.

Mechanical industry

• Wear-resistant parts: Bearings, seals, valve seats, nozzles, etc.
• Cutting tools: Compound with boron nitride (cBN) and titanium nitride (TiN) to improve performance.

Semiconductors and electronics

• Substrates and packaging: Used for heat dissipation substrates of semiconductor devices to meet high thermal conductivity requirements.
• Photolithography machine parts: High-precision silicon carbide structural parts are domestically produced through gel injection molding technology.

Energy and environmental protection

• Heat exchangers and burners: High-temperature corrosion resistance is suitable for gas turbines and industrial furnaces.
• New energy vehicles: Battery cooling components and high-temperature components.

Aerospace and military

• Armor materials: Used for bulletproof armor, with both lightweight and high energy absorption capabilities.
• Engine parts: Turbocharger rotors and high-temperature resistant structural parts.

Other fields

• Medical: Biocompatible components such as artificial joints.
• Refractory materials: Kiln furniture, crucibles and metallurgical furnace linings.