Modern alumina (Al2O3) products are among the strongest and hardest of all ceramic materials. They also have a high dielectric strength and at elevated temperatures, such as those encountered in many applications, their electrical resistance is excellent.
Alumina ceramics also feature very high mechanical strength, high thermal conductivity, and high resistance to chemical and corrosion attack at room and elevated temperatures. Further, this valuable class of materials can be made extremely hard - second only to diamond on the Mohs' scale, for resistance to wear and abrasion.
Many of alumina's outstanding properties can be enhanced through variation in manufacturing methods and in chemistry. Texas Technical Ceramics, Inc. has earned a reputation for achieving dimensionally accurate alumina parts with excellent quality and reproducibility.
Alumina
Properties
|
Units
|
ACT 800-850
|
ACT 900,920,960
|
ACT 990,997,999
|
ACTMA 99
|
Alumina Content |
|
80-85%
|
90-96%
|
> 99.5%
|
99%
|
General Application |
|
Lower Cost Electrical & Mechanical
|
High Strength, Wear Resistant, Electronic, Insulating, Mechanical, Structural & Metalizing
|
Extremely High Purity, Temperature & Strength; Excellent Corrosion & Wear Resistance
|
Porous, Easily Degassed & Machinable
|
Color (Fired) |
|
White
|
White
|
Off White
|
White
|
Porosity |
%
|
0-.05
|
0-.05
|
0-.05
|
Variable
|
Density |
gm/cm3
|
3.45-3.50
|
3.55-3.75
|
3.75-3.95
|
2.4
|
Flexural Strength |
kpsi
|
35.0-40.0
|
40.0-50.0
|
50.0-55.0
|
-
|
Comprehensive Strength |
kpsi
|
260.0
|
> 300.0
|
> 300.0
|
-
|
Tensile Strength |
kpsi
|
15.0-20.0
|
20.0-28.0
|
20.0-28.0
|
-
|
Linear Coefficient of Thermal Expansion |
(cm/cm/°C)
25-300°C
25-700°C
|
5.9X10-6
6.5X10-6
|
6.3X10-6
7.0X10-6
|
6.5X10-6
7.5X10-6
|
6.5X10-6
7.5X10-6
|
Dielecctric Constant at 25°C |
1 MH
10 MH
|
8.5-8.9
8.4-8.8
|
9.2-9.8
9.0-9.6
|
9.5-9.9
9.3-9.7
|
-
|
Dielectric Strength |
Volt/mil
|
200
|
225
|
225
|
-
|
Te Value |
°F
°C
|
1472
800
|
> 1832
> 1000
|
> 1832
> 1000
|
> 1832
> 1000
|
Thermal Conductivity at 25°C |
cal/sec/cm2/cm/°C
|
.03-.04
|
.04-.06
|
.07-.08
|
-
|
Thermal Shock |
|
Good
|
Good
|
Good
|
Good
|
Safe Use
Temperature |
°F
°C
|
2550
1400
|
3000-3100
1650-1700
|
3275
1800
|
3275
1800
|