Synthetic Sapphire vs. Low Expansion Glass-ceramic
Synthetic sapphire belongs to the oxide-based engineering ceramics classification, while low expansion glass-ceramic belongs to the glass and glass-ceramics. There are 20 material properties with values for both materials. Properties with values for just one material (5, in this case) are not shown.
For each property being compared, the top bar is synthetic sapphire and the bottom bar is low expansion glass-ceramic.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 450 | |
| 83 |
| Flexural Strength, MPa | 1090 | |
| 35 |
| Knoop Hardness | 1860 | |
| 530 |
| Poisson's Ratio | 0.28 | |
| 0.22 |
| Tensile Strength: Ultimate (UTS), MPa | 2470 | |
| 53 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 2000 | |
| 690 |
| Specific Heat Capacity, J/kg-K | 760 | |
| 800 |
| Thermal Conductivity, W/m-K | 30 | |
| 1.5 |
| Thermal Expansion, µm/m-K | 5.3 | |
| 1.7 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 10 | |
| 5.7 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 17 | |
| 11 |
Otherwise Unclassified Properties
| Density, g/cm3 | 4.0 | |
| 2.4 |
| Light Transmission Range, µm | 0.17 to 5.5 | |
| 0.5 to 2.7 |
| Refractive Index | 1.8 | |
| 1.5 |
Common Calculations
| Stiffness to Weight: Axial, points | 63 | |
| 19 |
| Stiffness to Weight: Bending, points | 64 | |
| 59 |
| Strength to Weight: Axial, points | 170 | |
| 6.1 |
| Strength to Weight: Bending, points | 100 | |
| 13 |
| Thermal Diffusivity, mm2/s | 9.9 | |
| 0.76 |
| Thermal Shock Resistance, points | 74 | |
| 28 |