Alumina vs. RPU
Alumina and RPU belong to fundamentally different material chemistries. Alumina is a ceramic material, while RPU is polymeric. Therefore, their performance will be even more dissimilar than would be suggested by the difference in properties. There are 15 material properties with values for both materials. Properties with values for just one material (16, 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 RPU.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 to 370 | |
| 2.2 |
| Flexural Strength, MPa | 260 to 430 | |
| 83 |
| Tensile Strength: Ultimate (UTS), MPa | 210 to 290 | |
| 60 |
Thermal Properties
| Specific Heat Capacity, J/kg-K | 870 to 940 | |
| 1750 |
| Thermal Conductivity, W/m-K | 14 to 30 | |
| 0.19 |
| Thermal Expansion, µm/m-K | 6.7 to 8.2 | |
| 63 |
Electrical Properties
| Dielectric Strength (Breakdown Potential), kV/mm | 8.9 to 12 | |
| 19 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 6.2 to 14 | |
| 13 |
Otherwise Unclassified Properties
| Density, g/cm3 | 3.4 to 4.1 | |
| 1.2 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 to 53 | |
| 1.0 |
| Stiffness to Weight: Bending, points | 57 to 62 | |
| 36 |
| Strength to Weight: Axial, points | 14 to 23 | |
| 14 |
| Strength to Weight: Bending, points | 19 to 28 | |
| 28 |
| Thermal Diffusivity, mm2/s | 3.7 to 10 | |
| 0.090 |
| Thermal Shock Resistance, points | 4.9 to 14 | |
| 31 |