WERKSTOFFEIGENSCHAFTSTABELLE

	Werkstoffeigenschaftstabelle der bekanntesten Keramiktypen

		ALUMINA Al2O3	ZIRCONIA ZrO2	NITRIDE Si3N4	CARBIDE SiC
MATERIAL PROPERTIES
Density	gr/cm3	3.8	6	3.3	3.2
Porosity	Vol %	0	0	0	0
MECHANICAL PROPERTIES
Hardness	N/mm2	20000	12000	16000	25000
Compressive strength	MPa	1700-2500	2000	2800	2500
E-modulus	GPa	300-350	200	275	410-450
Fracture toughness	MPa*m	4	9-15	6-7	3-4
Bending strength	N/mm2	300-340	800-1400	750-850	300-550
THERMAL PROPERTIES
Max. use temperature °C	In air In inert gas	1650-1900 1650-1900	900-1200 900-1200	1000-1400 1300-1800	1400-1600 2000
Thermal expansion	10-6/K	7.0-9.0	8.0-11.0	3.0-4.0	4.0
Thermal conductivity	W/mK at 20°C	20-30	2-3	35	110
ELECTRICAL PROPERTIES
Electrical resistivity	Ohm.cm at 400°C	1012	1010	1011	10-50

When designing advanced ceramic components the right material choice is very important. One could roughly state the following about the different ceramics

• Al₂O₃ To be used when thermal and electrical properties are important. Has a good mechanical strength and wear resistance property.
• ZrO₂ To be used when mechanical (toughness) properties are important. Has a low thermal conductivity. Has outstanding surface finishing possibilities.
• Si₃N₄ To be used when extreme mechanical properties are important. Has also good thermal and electrical properties.
• SiC To be used when extreme mechanical properties at high temperature levels are important. Has a low electrical resistivity.