Silicon Carbide  

Silicon carbide is available in two forms, reaction bonded and sintered.

Both materials are ultra hard and have a high thermal conductivity. This has led to silicon carbide being used in bearing and rotary seal applications where the increased hardness and conductivity improves seal and bearing performance.

Reaction bonded silicon carbide (RBSC) has good properties at elevated temperatures and can be used in refractory applications.

Silicon carbide materials exhibit good erosion and abrasive resistance, these properties can be utilised in a variety of applications such as spray nozzles, shot blast nozzles and cyclone components.

Silicon Carbide Production

Silicon Carbide is derived from powder or grain, produced from carbon reduction of silica. It is produced as either fine powder or a large bonded mass, which is then crushed. To purify (remove silica) it is washed with hydrofluoric acid.

There are three main ways to fabricate the commercial product. The first method is to mix silicon carbide powder with another material such as glass or metal, this is then treated to allow the second phase to bond.

Another method is to mix the powder with carbon or silicon metal powder, which is then reaction bonded.

Finally silicon carbide powder can be densified and sintered through the addition of boron carbide or other sintering aid. It should be noted that each method is suited to different applications.

Properties:

• High thermal conductivity
• Low thermal expansion coefficient
• Outstanding thermal shock resistance
• Extreme hardness
• Semiconductor
• Refractive index greater than a diamond