Silicon Nitride vs. Synthetic Sapphire
Silicon nitride belongs to the non-oxide engineering ceramics classification, while synthetic sapphire belongs to the oxide-based engineering ceramics. There are 16 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is silicon nitride and the bottom bar is synthetic sapphire.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 600 to 2950 | |
| 2700 |
| Elastic (Young's, Tensile) Modulus, GPa | 140 to 310 | |
| 450 |
| Flexural Strength, MPa | 130 to 810 | |
| 1090 |
| Fracture Toughness, MPa-m1/2 | 3.1 to 6.2 | |
| 1.9 |
| Poisson's Ratio | 0.24 to 0.27 | |
| 0.28 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 1000 to 1330 | |
| 2000 |
| Specific Heat Capacity, J/kg-K | 720 to 800 | |
| 760 |
| Thermal Conductivity, W/m-K | 12 to 31 | |
| 30 |
| Thermal Expansion, µm/m-K | 2.5 to 3.2 | |
| 5.3 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 8.0 to 10 | |
| 10 |
| Dielectric Strength (Breakdown Potential), kV/mm | 18 | |
| 9.9 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 11 to 12 | |
| 17 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.2 to 3.4 | |
| 4.0 |
Common Calculations
| Stiffness to Weight: Axial, points | 34 to 53 | |
| 63 |
| Stiffness to Weight: Bending, points | 65 to 78 | |
| 64 |
| Thermal Diffusivity, mm2/s | 7.5 to 13 | |
| 9.9 |