Hardness

Ceramics have remarkable mechanical properties in comparison with metals and plastics. Although all types of ceramics offer exceptionally high levels of compressive strength, other properties such as density, hardness, resistance to wear, impact resistance and bending strength tend to vary.

Description

The hardness of a material is determined by how well it resists deformation. Ceramics are generally very hard materials that very rarely change their shape under stress, right up until breaking point. Aluminium oxide is the second hardest natural material after diamond, and boron carbide and silicon carbide are two other extremely hard synthetic materials.

These different types of ceramics are offered by our members.

Application markets

Hardness is an essential property in ballistic protection, which is why Al2O3, SiC and B4C are so widely used in the military. Hardness is often associated with resistance to wear, and is therefore sought after in multiple fields of application, such as the medical sector or in mechanics.

Comparative table of properties

Comparative table of mechanical 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.

Raw material
Finished product

Related members:

27, rue du petit Theil
87280 Limoges
12 rue Lirenne
25480 ECOLE VALENTIN
22, rue de Lamirault Zae de Lamirault-Collegien
77090 Collegien
6, rue des frênes
91160 Ballainvilliers
59, avenue Etienne Billières
31300 Toulouse
20, rue des Champs,
91830 Le Coudray Montceaux
Z.I. No.1 Rue de l’Industrie
27000 Evreux