Boron carbide is the third hardest known material, only surpassed by diamond and cubic boron nitride.
Typical physical properties of boron carbide and silicon carbide:
| Property | Unit | B4C | SiSiC |
|---|---|---|---|
| Density | g/cm³ | >2.48 | >3.07 |
| Hardness (Vickers) | GPa | 32 | 24 |
| Compressive Strength | MPa | 2760 | 2100 |
| Flexural Strength | MPa | 360 | 290 |
| Young's Modulus | GPa | 455 | 320 |
| Poisson - Ratio | - | 0.16 | 0.17 |
| Weibull Modulus | - | 10 | 12 |
| Thermal Expansion (20-1000°C) | 10-6K-1 | 5.6 | 4,6 |
| Thermal Conductivity (20°C) | W/mK | 30 | 80 |
| Specific Electrical Resistivity (20°C) | Ohm cm | 0.1 | 0.1 |
Wear resistance in comparison:
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