Synthetic Sapphire vs. Boron Carbide
Synthetic sapphire belongs to the oxide-based engineering ceramics classification, while boron carbide belongs to the non-oxide engineering 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 boron carbide.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 2700 | |
| 1710 to 2200 |
| Elastic (Young's, Tensile) Modulus, GPa | 450 | |
| 240 to 460 |
| Flexural Strength, MPa | 1090 | |
| 170 to 410 |
| Fracture Toughness, MPa-m1/2 | 1.9 | |
| 2.5 to 3.5 |
| Knoop Hardness | 1860 | |
| 2600 to 3200 |
| Poisson's Ratio | 0.28 | |
| 0.17 to 0.19 |
| Tensile Strength: Ultimate (UTS), MPa | 2470 | |
| 350 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 2000 | |
| 1000 to 2500 |
| Specific Heat Capacity, J/kg-K | 760 | |
| 950 |
| Thermal Conductivity, W/m-K | 30 | |
| 31 to 90 |
| Thermal Expansion, µm/m-K | 5.3 | |
| 4.5 to 5.6 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 10 | |
| 6.4 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 17 | |
| 0 to 11 |
Otherwise Unclassified Properties
| Density, g/cm3 | 4.0 | |
| 2.1 to 2.7 |
Common Calculations
| Stiffness to Weight: Axial, points | 63 | |
| 63 to 100 |
| Stiffness to Weight: Bending, points | 64 | |
| 91 to 100 |
| Strength to Weight: Axial, points | 170 | |
| 37 to 47 |
| Strength to Weight: Bending, points | 100 | |
| 42 to 53 |
| Thermal Diffusivity, mm2/s | 9.9 | |
| 16 to 38 |
| Thermal Shock Resistance, points | 74 | |
| 9.7 to 20 |