Optical Silicon vs. Silicon Carbide
Optical silicon belongs to the non-glass optical ceramics classification, while silicon carbide belongs to the non-oxide engineering ceramics. There are 18 material properties with values for both materials. Properties with values for just one material (7, in this case) are not shown.
For each property being compared, the top bar is optical silicon and the bottom bar is silicon carbide.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 120 | |
| 2780 to 3900 |
| Elastic (Young's, Tensile) Modulus, GPa | 150 | |
| 370 to 490 |
| Flexural Strength, MPa | 300 | |
| 410 to 600 |
| Fracture Toughness, MPa-m1/2 | 3.5 | |
| 3.4 to 4.6 |
| Knoop Hardness | 1130 | |
| 2500 to 2900 |
| Poisson's Ratio | 0.28 | |
| 0.14 to 0.21 |
| Tensile Strength: Ultimate (UTS), MPa | 110 | |
| 210 to 370 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 1350 | |
| 500 to 1590 |
| Specific Heat Capacity, J/kg-K | 700 | |
| 670 to 1180 |
| Thermal Conductivity, W/m-K | 150 | |
| 120 to 170 |
| Thermal Expansion, µm/m-K | 3.0 | |
| 4.0 to 4.5 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.3 | |
| 3.0 to 3.2 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 | |
| 69 to 84 |
| Stiffness to Weight: Bending, points | 75 | |
| 79 to 82 |
| Strength to Weight: Axial, points | 13 | |
| 18 to 34 |
| Strength to Weight: Bending, points | 22 | |
| 24 to 38 |
| Thermal Diffusivity, mm2/s | 93 | |
| 38 to 79 |
| Thermal Shock Resistance, points | 18 | |
| 6.9 to 18 |