Optical Silicon vs. Silicon Nitride
Optical silicon belongs to the non-glass optical ceramics classification, while silicon nitride belongs to the non-oxide engineering ceramics. There are 14 material properties with values for both materials. Properties with values for just one material (12, in this case) are not shown.
For each property being compared, the top bar is optical silicon and the bottom bar is silicon nitride.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 120 | |
| 600 to 2950 |
| Elastic (Young's, Tensile) Modulus, GPa | 150 | |
| 140 to 310 |
| Flexural Strength, MPa | 300 | |
| 130 to 810 |
| Fracture Toughness, MPa-m1/2 | 3.5 | |
| 3.1 to 6.2 |
| Poisson's Ratio | 0.28 | |
| 0.24 to 0.27 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 1350 | |
| 1000 to 1330 |
| Specific Heat Capacity, J/kg-K | 700 | |
| 720 to 800 |
| Thermal Conductivity, W/m-K | 150 | |
| 12 to 31 |
| Thermal Expansion, µm/m-K | 3.0 | |
| 2.5 to 3.2 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 12 | |
| 8.0 to 10 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.3 | |
| 2.2 to 3.4 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 | |
| 34 to 53 |
| Stiffness to Weight: Bending, points | 75 | |
| 65 to 78 |
| Thermal Diffusivity, mm2/s | 93 | |
| 7.5 to 13 |