Ceramics offer exceptional mechanical properties compared to metals and plastics. Compressive strength is very high for all the 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
Flexural strength is one of the weak points of ceramics: ceramics with low flexibility (high Young's Modulus), compared to metals, for instance, generally have fairly low flexural strength. There is, however, a type of ceramic preferred for applications where the user requires flexural strength in addition to other mechanical properties: zirconium oxide (or zirconia), and, in particular, Y-TZP zirconia (yttria-stabilised zirconia) or ATZ. To a lesser extent, silicon nitride or certain alumina may also be used.
Application markets
These materials are used in a wide variety of business sectors: engineering (equipment manufacturers, special machines, processing equipment), defence and medical.
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.