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Materials |
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Silicon Carbide (SiC) is one of the most popular high performance tribo-materials, which has been commercially available for more than twenty-five years. Its features include:
· Excellent abrasion and wear resistance
· Excellent corrosion resistance
· Low coefficient of friction
· Low coefficient of thermal expansion
· High thermal conductivity
· Hardness greater than Tungsten Carbide
Different grades of Silicon Carbide are available as following:
· Reaction Bonded Silicon Carbide (RB SiC) – a very economical material which gives excellent wear characteristics, as well as good chemical resistance.
· Sintered Silicon Carbide (SSiC) – the absence of free silicon makes it most resistant to chemically-aggressive fluids, and ideal for high temperature applications.
· Graphite-Loaded Silicon Carbide – this is a composite of silicon carbide and free graphite. Graphite is added to RB SiC (RB SiC + C) or SSiC (SSiC + C), to improve tribological behavior by enhanced lubricity.
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| Parameter |
Unit |
RB SiC |
SSiC |
| Density |
g/cm3 |
3.0 - 3.05 |
3.1 |
| Free Silicon Content |
- |
12% |
- |
| Crystal Size |
μm |
8 - 20 |
5 - 7 |
| Hardness |
Rockwell |
HRA 90 |
HRA 93 |
| Compressive Strength |
MPa |
2700 |
3000 |
| Flexural Strength |
MPa |
400 |
400 |
| Fracture Toughness |
MPa |
4.3 |
4.5 |
| Elastic Modulus |
GPa |
390 |
410 |
| Poisson's Ratio |
- |
0.15 |
0.15 |
| Coefficient of Thermal Expansion |
1 x 10-6 / K |
4.3 |
4.3 |
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