Advanced ceramics offer exceptional mechanical properties compared to metals and plastics. Compressive strength is very high for all groups of advanced ceramics, but other properties, such as hardness, resistance to wear, shock resistance and flexural strength, vary from one type of ceramic to the next.
Description
The elasticity of a material is defined by Young's Modulus expressed in GPa. The lower the modulus value, the more the material will deform.
In contrast to metals and plastics, ceramics are not very elastic. Their mechanical stiffness distinguishes these materials, and while this is generally considered an advantage for their use in harsh environments, it can also be a weakness when they undergo mechanical bending or torsion loads. Out of all the different advanced ceramics, zirconia has the greatest "elasticity" with a Young's Modulus in the region of 200 GPa, while alumina, silicon carbides, aluminium nitrides and silicon are the least elastic with a Young's Modulus of between 300 and 400 GPa.
Application markets
All areas of application are affected by this property. It is evident that the choice of use of an advanced ceramic is often based on the criterion of good mechanical strength.
Comparative table of properties
| Values at ambient temperature – 20°c |
Density (g/cm3) |
Resistance to compression (MPa) |
Resistance to bending (MPa) |
Young's modulus (GPa) |
Hardness (Vickers -GPa) |
Fracture toughness K(Ic) |
| Alumina (94 to 99.8 % ) | 3.6 to 3.9 | 1700 to 2500 | 250 to 350 | 350-370 | 12 to 18 | 4 to 5 |
| Alumina-zirconia composites | 4.0 | 2000 | 450 | 350 | 14 | 5 to 6 |
| Zirconia MgO | 5.5 | >1700 | 550 to 700 | 170 to 200 | 11 to 12 | 6 to 8.5 |
| Zirconia Y-TZP | 6.0 | 2000 to 2500 | 900 to 1250 | 200 to 220 | 12 to 16 | 10 to 13 |
| Aluminium nitride | 3.3 | 2000 | >300 | 310 | - | 3 |
| Silicon nitride | 3.2 | 2500 to 3000 | 650 to 900 | 300 to 315 | 15 to 16 | 7.5 to 8 |
| Silicon carbide | 3.1 | 2500 to 3900 | 400 to 550 | 410 | 24.5 to 28 | 4 to 4.6 |
| Boron carbide | 2.5 | >1500 | 425 | 440 | 28 | 3 to 4 |
Acceptable: + ; Good: ++ ; Very good: +++.
These values are for information only and do not constitute a contractual obligation.