Silicon carbide (SiC) is an exceedingly hard chemical synthetically produced crystalline compound containing silicon and carbon. It is one of the hardest known substances today, as it competes closely with substances like diamond and boron carbide.
Typical properties：
- Great mechanical strength and hardness
- High thermal stability
- Low thermal expansion
- Very good thermal shock resistance
- Variable electrical conductivity
- Highly corrosion resistance
- Good abrasion resistance
Applications in a wide range of industries:
- Semiconductors in electronics for circuit elements.
- As abrasives used for grinding wheels, cutting tools, sandpaper, cloth products, etc.
- Used in Military Bulletproof Armor due to its hardness.
- Wear parts, such as seals, bearings, and pump impellers.
- Refractory application in the production of ceramics, steel, iron, nonferrous metals, chemicals, etc.
- Aerospace components
- Paper manufacturing
- Pipe system
Silicon carbide ceramics differ depending on the manufacturing methods. They include OBSiC, SiSiC, SSiC, RSiC, NSiC. These ceramics have different porosities, densities, and properties.
1. OBSiC (Oxide-Bonded Silica Carbide)
OBSiC is made by bonding silicon carbide (SiC) particles together with an oxide binder. The oxide binder is typically silica (SiO2).
Excellent high-temperature resistance up to 1450℃.
OSiC is especially suitable for applications with high demands e.g.
- Sintering of ceramics, magnetic materials, electrical ceramics etc.
- Grinding wheel
2. SiSiC (Sintered Silicon Carbide)
Also named RBSiC (Reaction-Bonded Silicon Carbide)
SiSiC consists of 80 – 90% of SiC and correspondingly 10 – 20% of metallic silicon. There is no shrinkage during the sintering process because of the composite manufacturing process.
However, the application temperature is limited to approx. 1380 °C . It is not recommended for use in aggressive alkaline environments with a pH value greater than 10.
SiSiC is highly suitable for the production of
- Kiln furniture, such as shelves, beams, and supports for ceramics, glass, metallurgy, and other industries
- Complex components of the machine
- Heating elements
- Components for the energy industry
- Mechanical seals for pumps, compressors, and other rotating equipment
- Semiconductor and electronics
- Mining and material handling
- Bulletproof armor in military
3. SSiC (Sintered Silicon Carbide)
SSiC is processed by pressureless sintering. It is made from SiC finest powder plus sinter additives and is sintered at 2000 to 2200°C.
In contrast to SiSiC, the SSiC parts may be recommended for use in virtually any aggressive media with pH ranging from 0 to 14.
SSiC is suitable for application e.g.
- Used as componenets for anticorrosion and heat exchanging for fine chemicals and pharmaceuticals.
- As high precision components for Semiconductors.
- Face seals for different types of oil/gas and chemical pumps, chemical pumps and valving.
- Wear parts of processing equipment, like nozzles, dies, etc.
- For high temperature resistance, like kiln furniture.
4. RSiC (Recrystallized Silicon Carbide)
RSiC is a high-purity material (SiC>99.5%) sintered by using evaporation-condensation without additives in a vacuum furnace. It can be cast or extruded into a wide range of flat and elongated shapes, such as plates, beams, tubes, and saggers.
RSiC’s unique microstructure gives it even better properties compared to other SiC materials. Its key feature is very high temperature. Max. Working temperature up to 1650℃.
Mainly application:
- Kiln furniture for technical ceramics, metallurgy, etc.
- Like Alumina industrial ceramic, Zirconia fine ceramics, etc.
5. NSiC (Nitride-Bonded Silicon Carbide)
NSiC is produced through nitridation, where a composite of 70-80% SiC powder and a nitrogen-containing 20-30% Si3N4, are heated to high temperatures in a nitrogen-rich atmosphere.
Max. working temperature is 1450℃. With superior thermal shock resistance, high-temperature strength, and wear resistance, excellent resistance to molten metal under high temperatures.
NSiC products application:
- As kiln furniture for ceramics, glass, and other industries. Such as plates, beams, supports
- Used in the production of metal casting components, like ladles, crucibles, saggers
- Wear-resistant components in metallurgy, mining, and chemical processing, e.g. nozzles, liners, plates
- Thermocouple protection tubes
- Burner components
Conclusion
Silicon carbide ceramics have several manufacturing methods.
And they are applied to various industries. If you have any questions about choosing which type of SiC ceramics for your application, please contact us for further recommendations. Firller will provide quality SiC ceramics obtained from different materials.
