Synthetic Sapphire vs. Graphite
Synthetic sapphire belongs to the oxide-based engineering ceramics classification, while graphite belongs to the non-oxide engineering ceramics. There are 13 material properties with values for both materials. Properties with values for just one material (14, 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 synthetic sapphire and the bottom bar is graphite.
Metric UnitsUS Customary Units
Mechanical Properties
Compressive (Crushing) Strength, MPa | 2700 | |
90 |
Elastic (Young's, Tensile) Modulus, GPa | 450 | |
21 |
Flexural Strength, MPa | 1090 | |
80 |
Tensile Strength: Ultimate (UTS), MPa | 2470 | |
18 |
Thermal Properties
Maximum Temperature: Mechanical, °C | 2000 | |
220 |
Thermal Conductivity, W/m-K | 30 | |
6.0 |
Thermal Expansion, µm/m-K | 5.3 | |
4.9 |
Otherwise Unclassified Properties
Density, g/cm3 | 4.0 | |
1.8 |
Common Calculations
Stiffness to Weight: Axial, points | 63 | |
6.7 |
Stiffness to Weight: Bending, points | 64 | |
53 |
Strength to Weight: Axial, points | 170 | |
2.9 |
Strength to Weight: Bending, points | 100 | |
8.7 |
Thermal Shock Resistance, points | 74 | |
12 |