Optical Silicon vs. CVD Diamond
Optical silicon belongs to the non-glass optical ceramics classification, while CVD diamond belongs to the non-oxide engineering ceramics. There are 17 material properties with values for both materials. Properties with values for just one material (8, in this case) are not shown.
For each property being compared, the top bar is optical silicon and the bottom bar is CVD diamond.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 150 | |
| 1050 |
| Fracture Toughness, MPa-m1/2 | 3.5 | |
| 5.5 |
| Poisson's Ratio | 0.28 | |
| 0.1 |
| Tensile Strength: Ultimate (UTS), MPa | 110 | |
| 750 |
Thermal Properties
| Specific Heat Capacity, J/kg-K | 700 | |
| 500 |
| Thermal Conductivity, W/m-K | 150 | |
| 1900 |
| Thermal Expansion, µm/m-K | 3.0 | |
| 1.0 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 12 | |
| 5.7 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.3 | |
| 3.5 |
| Light Transmission Range, µm | 1.2 to 15 | |
| 0.22 to 100 |
| Refractive Index | 3.5 | |
| 2.4 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 | |
| 170 |
| Stiffness to Weight: Bending, points | 75 | |
| 96 |
| Strength to Weight: Axial, points | 13 | |
| 59 |
| Strength to Weight: Bending, points | 22 | |
| 52 |
| Thermal Diffusivity, mm2/s | 93 | |
| 1080 |
| Thermal Shock Resistance, points | 18 | |
| 51 |