Alumina
The WESGO alumina family includes four standard, dense, vacuum-tight compositions containing from 94% to 99.9% alumina to cover a wide range of applications.
As alumina content increase, properties such as chemical resistance, thermal conductivity, dielectric strength and resistivity generally increase.
| Units | Properties/Material | Alumina | Sintered Fused Silica | ||
| Tradenames | AL-995® | AL-500® | AL-300® | HVX | |
| - | Description | 99.5%Al2O3 | 94%Al2O3 | 97.6%Al2O3 | 99.9%SiO2 |
| - | Color | White | White | White | White |
| KPSI Mpa | Flexural Strength | 45 310 | 49 335 | 43 296 | 2.2 15 |
| Knoop (kg/mm2) | Hardness | 1600 | 1250 | - | - |
| % | Porosity (water absorption) | 0 | 0 | 0 | 22 |
| g/cc | Density | 3.86 | 3.67 | 3.76 | 1.35 |
| psi x 106 | Youngs Modulus (25°C) | 54 | 45 | - | - |
| W/m° K | Thermal Conductivity | 29 | 21 | 27 | 0.9 |
| �L/Lx10-6/°C | Coefficient of Thermal Expansion (RT-300°C) | 7.4 | 6.7 | - | 0.5 |
| °C | Max Continuous Use Temperature (no load, air) | 1725 | 1600 | 1650 | 1100 |
| K' | Dielectric Constant (25°C, 1Mhz) | 9.6 | 9.1 | 9.5 | 3.6 |
| Tan � | Dissipation Factor (25°C, 1Mhz) | 0.00004 | 0.00026 | 0.00026 | - |
| ohm-cm | (25°C) Resistivity (300°C) | >1014 >2 x 1011 | >1014 >2 x 1012 | >1014 >2 x 1012 | >1014 |
* Values quoted are typical of results obtained from reliable testing and should be used for guidance only. Call Wesgo for details on other available materials.