Alumina vs. Silicon Nitride
Alumina belongs to the oxide-based engineering ceramics classification, while silicon nitride belongs to the non-oxide engineering ceramics. There are 17 material properties with values for both materials. Properties with values for just one material (9, in this case) are not shown.
For each property being compared, the top bar is alumina and the bottom bar is silicon nitride.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 1920 to 2750 | |
| 600 to 2950 |
| Elastic (Young's, Tensile) Modulus, GPa | 220 to 370 | |
| 140 to 310 |
| Flexural Strength, MPa | 260 to 430 | |
| 130 to 810 |
| Fracture Toughness, MPa-m1/2 | 3.7 to 7.2 | |
| 3.1 to 6.2 |
| Poisson's Ratio | 0.22 to 0.24 | |
| 0.24 to 0.27 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 650 to 1730 | |
| 1000 to 1330 |
| Maximum Thermal Shock, °C | 200 to 300 | |
| 290 to 750 |
| Specific Heat Capacity, J/kg-K | 870 to 940 | |
| 720 to 800 |
| Thermal Conductivity, W/m-K | 14 to 30 | |
| 12 to 31 |
| Thermal Expansion, µm/m-K | 6.7 to 8.2 | |
| 2.5 to 3.2 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 7.8 to 11 | |
| 8.0 to 10 |
| Dielectric Strength (Breakdown Potential), kV/mm | 8.9 to 12 | |
| 18 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 6.2 to 14 | |
| 11 to 12 |
Otherwise Unclassified Properties
| Density, g/cm3 | 3.4 to 4.1 | |
| 2.2 to 3.4 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 to 53 | |
| 34 to 53 |
| Stiffness to Weight: Bending, points | 57 to 62 | |
| 65 to 78 |
| Thermal Diffusivity, mm2/s | 3.7 to 10 | |
| 7.5 to 13 |