Alumina vs. PEI
Alumina and PEI belong to fundamentally different material chemistries. Alumina is a ceramic material, while PEI is polymeric. Therefore, their performance will be even more dissimilar than would be suggested by the difference in properties. There are 18 material properties with values for both materials. Properties with values for just one material (19, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is alumina and the bottom bar is PEI.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 1920 to 2750 | |
| 140 to 180 |
| Elastic (Young's, Tensile) Modulus, GPa | 220 to 370 | |
| 3.4 to 5.6 |
| Flexural Strength, MPa | 260 to 430 | |
| 140 to 210 |
| Tensile Strength: Ultimate (UTS), MPa | 210 to 290 | |
| 110 to 160 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 650 to 1730 | |
| 170 |
| Specific Heat Capacity, J/kg-K | 870 to 940 | |
| 1050 to 1220 |
| Thermal Conductivity, W/m-K | 14 to 30 | |
| 0.18 to 0.23 |
| Thermal Expansion, µm/m-K | 6.7 to 8.2 | |
| 20 to 53 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 7.8 to 11 | |
| 3.2 to 3.7 |
| Dielectric Strength (Breakdown Potential), kV/mm | 8.9 to 12 | |
| 30 to 33 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 6.2 to 14 | |
| 14 to 15 |
Otherwise Unclassified Properties
| Density, g/cm3 | 3.4 to 4.1 | |
| 1.3 to 1.5 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 to 53 | |
| 1.5 to 2.1 |
| Stiffness to Weight: Bending, points | 57 to 62 | |
| 39 |
| Strength to Weight: Axial, points | 14 to 23 | |
| 24 to 30 |
| Strength to Weight: Bending, points | 19 to 28 | |
| 40 to 44 |
| Thermal Diffusivity, mm2/s | 3.7 to 10 | |
| 0.11 to 0.14 |
| Thermal Shock Resistance, points | 4.9 to 14 | |
| 44 to 100 |