Alumina
Aluminas (aluminum oxide, Al2O3) are the most commonly used technical ceramics due to their generally useful properties and good price/performance ratio. Alumina ceramics are commonly subdivided according to their alumina content ranging from 80% to more than 99%. Higher purity alumina demonstrates enhanced wear and corrosion resistance — creating a continuous scale of various alumina grades, compositions, and performance.
Aluminas are used in both general use and specialized applications. A grade is selected to fit the application environment. Alumina compositions and microstructures can be formulated to meet the specific performance requirements of more demanding applications.
- General use
- Wear resistance
- Electrical insulator
- Dielectric strength
- Low dielectric loss
Ceramic Expertise
CoorsTek has developed over 100 unique alumina compositions, optimized for specific application requirements. Let our experts help you determine the best-fit material for your application.
Brochure Downloads
Download the Advanced Alumina brochure
Download the Advanced Alumina for Semiconductor brochure
Alumina properties
| AD-94 | AD-96 | FG-995 | AD-995 | PLASMAPURE™ AD-998 |
PLASMAPURE-UC™ ALUMINA |
||
| Properties | Units | Nom. 94% Al2O3 | Nom. 96% Al2O3 | Nom. 98.5% Al2O3 | Nom. 99.5% Al2O3 | Nom. 99.8% Al2O3 | Nom. 99.9% Al2O3 |
| Density | g/cm³ | 3.70 | 3.72 | 3.80 | 3.90 | 3.92 | 3.92 |
| Color | — | WHITE | WHITE | WHITE | IVORY | IVORY | IVORY |
|
4-PT Flexural Strength |
MPa (psi x 10³) |
308 | 343 | 298 | 300 | 320 | 360 |
| Elastic Modulus (20° C) |
GPa (psi x 106) |
303 | 303 | 350 | 370 | 380 | 386 |
| Poisson’s Ratio (20° C) |
— | 0.21 | 0.21 | 0.22 | 0.22 | 0.22 | 0.22 |
| Compressive Strength (20° C) |
MPa (psi x 10³) |
2103 | 2068 | 2500 | 2600 | 2650 | 2700 |
| Hardness (Knoop 1000gm) |
GPa (kg/mm²) |
11.5 | 11.5 | 13.7 | 14.1 | 14.1 | 14.5 |
| Fracture Toughness (KIC) |
MPa m1/2 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 |
| Thermal Conductivity (20° C) |
W/m | 22.4 | 24.7 | 27.5 | 30.0 | 31.0 | 33.0 |
| Coefficient of Thermal Expansion (25-1000°C) | 1x10-6/°C | 8.2 | 8.2 | 8.2 | 8.2 | 8.2 | 8.2 |
| Specific Heat (100° C) |
J/kg*K | 880 | 880 | 880 | 880 | 880 | 870 |
| Dielectric Strength (6.35mm) |
ac-kV/mm (ac V/mil) |
8.3 | 8.3 | 8.7 | 8.7 | 8.7 | 8.7 |
| Dielectric Constant (1 MHz) |
25° C | 9.1 | 9.0 | 9.6 | 9.7 | 9.8 | 9.8 |
| Dielectric Loss (tan delta) (1 MHz 25° C) |
25° C | 0.0004 | 0.0002 | 0.0002 | 0.0001 | < 0.0001 | <0.0001 |
| Volume Resistivity (25° C) |
ohm-cm | >1014 | >1014 | >1014 | >1014 | >1014 | >1015 |
| (500° C) | ohm-cm | 4 x 109 | 4 x 109 | 2 x 1010 | 2 x 1010 | 2 x 1011 | 1 x 1012 |
| (1000° C) | ohm-cm | 5 x 105 | 1 x 106 | 2 x 106 | 2 x 106 | 2 x 107 | 1 x 107 |