Comparison between properties

	Oxides				Carbide	Nitride
	Al ₂O ₃	ZrO2/Y2O3	ZrO2/MgO	MgO	SiC	Si3N4 Reaction sintered	Si3N4 Hot pressed	ALN
Physical properties
Density (g/cm3)	3,9	5,9	5,75	3,58	3,2	3,27	3,29	3,26
Molecular weight (g/mole)	102	-	-	40,4	40,1	140	140	41
Maximum service temperature air (°C)	1700- 1800	1500	1000	2200	1500	1200- 1500	1100- 1600	1000- 1800
Mechanical properties
Hardness (Mohs)	9	-	-	5,5	9	-	-	7
Modulus of elasticity (GPa)	300-400	200	200	250-300	420	170-220	280-310	318
Poisson's ratio	0,25	-	-	0,18	0,14	0,25-0,26	0,27	0,25
Fracture toughness (MPa.m1/2)	2-3	7-13	6-10	-	2,5-3,5	3,5-5	6,1	4,5
Electrical properties
Dielectric constant	9-10	-	-	9-10	-	10	10	9,2
Electrical resistivity at 20°C (Ohm.cm)	>10 ₁₄	10 ₁₃-10 ₁₄	>10 ₁₀	-	10 ₂-10 ₆	>10 ₇	10 ₁₂- 10 ₁₅	>10 ₁₄
Dielectric strength (kV/mm)	10-20	9	2-10	-	-	-	-	15
Thermal properties
Specific heat (J/K/kg)	900	400-500	420	870-880	750	690	680-800	800
Thermal conductivity (W/m/K) at 20°C	26-35	2,2-3,2	1,5-2,5	40-50	63-155	9-30	15-43	180
Coefficient of thermal expansion ( 10-6) from 20 to 1000°C	8-9	10-11	5-16	10-13	4-5	3	3,3	4,4-5,3
Melting point (°C)	2050	2590	-	2800	2500	1900	1900	2200

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