Optical Silicon vs. SiAlON
Optical silicon belongs to the non-glass optical ceramics classification, while SiAlON belongs to the non-oxide engineering ceramics. There are 20 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.
For each property being compared, the top bar is optical silicon and the bottom bar is SiAlON.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 120 | |
| 2620 |
| Elastic (Young's, Tensile) Modulus, GPa | 150 | |
| 290 |
| Flexural Strength, MPa | 300 | |
| 680 |
| Fracture Toughness, MPa-m1/2 | 3.5 | |
| 6.3 |
| Knoop Hardness | 1130 | |
| 1700 |
| Poisson's Ratio | 0.28 | |
| 0.23 |
| Shear Modulus, GPa | 80 | |
| 120 |
| Tensile Strength: Ultimate (UTS), MPa | 110 | |
| 190 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 1350 | |
| 1200 |
| Specific Heat Capacity, J/kg-K | 700 | |
| 880 |
| Thermal Conductivity, W/m-K | 150 | |
| 19 |
| Thermal Expansion, µm/m-K | 3.0 | |
| 3.6 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 12 | |
| 9.3 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.3 | |
| 3.3 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 | |
| 50 |
| Stiffness to Weight: Bending, points | 75 | |
| 67 |
| Strength to Weight: Axial, points | 13 | |
| 16 |
| Strength to Weight: Bending, points | 22 | |
| 22 |
| Thermal Diffusivity, mm2/s | 93 | |
| 6.4 |
| Thermal Shock Resistance, points | 18 | |
| 13 |