Alumina

Material		Alumina Al2O3				Zirconia ZrO₂			Mixed oxides ZrO₂/Al₂O₃			Silicon carbide SIC			Silicon nitride Si3N4	Boron nitride	Metal
						ATZ	ZTA
Brief description		Al2O3 purity 96%	Al₂O₃ purity 99.7%	Mg-PSZ MgO partially stabilized	Y-TZP Y₂O3 partially stabilized	ZrO₂ particle-reinforced	Al₂O₃ particle-reinforced	SiSiC Si-infiltrated with 8-12% free Silicon	SSiC sintered without free silicon	HP SIC hot-pressed without free silicon	HP SN hot-pressed	SSN sintered	HP BN* hot-pressed	C-15* plain steel
Color		white	white	yellow	white	white	white	black	black	black	black	grey	white	-
Structural properties
Density	g/cm³	3.7	3.9	5.7	>6.0	5.5	4.1	3.1	3.1	3.2	3.2	3.22	2	7.87
Open porosity	%	0	0	0	0	0	0	0	0	0	0	0	0	0
Average crystal size	µm	10	5	50	0.7	0.7	0.5	15	1	10	5	5	-	-
Mechanical properties
Vickers hardness (HV₁₀)	MPa	1400	1800	1200	1300	1400	1700	2200	2500	2500	1600	1450	190	700
Compressive strength	MPa	2800	2800	1600	2200	2100	2600	1200	2200	2900	2500	2500	160	1000
Flexural strength	MPa	290	340	500	1000	820	600	320	420	430	850	750	70/30**	450
Fracture toughness	MPam^½	-	4.3	7.0	10.5	7.0	7.0	-	3.2	3.2	6.0	7.0	-	-
Elastic modulus*	GPa	350	380	200	200	220	360	350	410	440	320	300	30/25**	210
Weibull modulus*	-	10	10	12	20	20	20	12	10	12	18	15	-	-
Poisson's ratio*	-	0.22	0.22	0.3	0.3	0.27	0.24	0.22	0.17	0.16	0.26	0.25	0.13	0.33
Thermal properties
max. Application temperature* under protective gas	°C	1600	1650	900	1200	1200	1000	1350	1800	1800	1300	1300	2400	400
max. Application temperature* in air	°C	1600	1650	900	1200	1200	1000	1350	1500	1500	1100	1100	850	300
Specific heat at 20°C	J/Kg K	900	900	550	500	600	700	950	650	1000	750	700	-	462
Thermal conductivity at 100°C	W/mK	25	30	2	2	6	25	85	75	90	35	35	35	50
Coefficient of thermal expansion(20°C - 1000°C)	10^-6K^-1	8.5	8.5	10.5	10.5	9	9	4.5	4.1	4.1	3.2	3.3	2.2	11
Thermal shock resistance*	K	180	190	260	300	300	250	400	350	450	400	450	-	-
Electrical properties
Volume resistivity at 20°C	Ωcm	10¹⁴	10¹⁴	10¹⁰	10⁹	10⁹	10⁹	0.2	10-100	10²	10¹⁰	10¹²	10¹⁴	0.0015
Volume resistivity at 400°C	Ωcm	10¹¹	10¹²	10⁴	10⁴	10⁴	10⁷	-	-	-	-	-	-	-
Volume resistivity at 1000°C	Ωcm	10⁴	10⁷	10³	10³	10²	10⁵	0.05	0.2	0.2	10⁷	10⁷	10⁹	-
Dielectric strength	kV/mm	>18	>25	-	-	-	-	-	-	-	-	-	39	-
Dielectric constant at 20°C and 1 GHz	-	8	9	>20	>20	>20	-	-	-	-	20	20	-	-
Dielectric loss factor (tgΔ) at 20°C and 1 GHz	-	5x10^-4	2x10^-4	-	-	-	-	-	-	-	-	-	-	-
Dielectric loss factor (tgΔ) at 20°C and 10 kHz	-	3x10^-4	1x10^-4	-	-	-	-	-	-	-	5x10-2	5x10-2	-	-

Alumina (Al2O3)

The economic all-around solution

Alumina is the leading material among Technical Ceramics and is the most commonly and widely used due to its superior versatile qualities such as material properties, ease of manufacture, wide availability and economic prices.

Specific properties
Applications

Specific properties

Very high use temperature

Very good electric insulation

Very high compressive strength

Medium mechanical strength

Medium thermal conductivity

Low density

Biocompatibility (food safe)

High corrosion resistance

Applications

Sealing and sliding elements in valves

Wear resistance in mechanical and plant engineering

Wire guides used in the cable and wire industry

Nozzles used in the pressure washing industry

Thermal protection tubes

High-temperature systems

Alumina (Al2O3)

The economic all-around solution

Specific properties

Applications

CERTIFICATION - ISO 9001:2015

SERVICE & LEGAL