With translucency properties similar to those of a single alumina crystal, translucent alumina ceramics allow diffusion transmission of practically the whole spectrum of visible light, and they are used as lighting components in products such as sodium lamps. At CoorsTek, we have focused on the high purity of translucent aluminum ceramics in addition to their excellent resistance to corrosion from fluorine gas and have developed new uses for them as semiconductor device components. Sapphal has a high level of purity and, at the same time, has a structure with uniform crystal grain size and high density which is nearly pore-free. Now, it has become possible to manufacture large size products and complex shapes, which had been considered very difficult previously.
SAPPHAL High-Purity Translucent Alumina Ceramics
Crystal organization of SAPPHAL
You can see that other alumina ceramics in comparison with SAPPHAL have etched holes and that numerous particles have been generated.
Sapphal is effective in preventing alkali and metal contamination.
|
Alumina content
|
% | 99.97 |
|---|---|---|
|
Bulk density
|
g/cm3 | 3.99 |
|
Absorption rate
|
% | 0 |
|
Average crystal diameter
|
 |
25 |
|
Bending strength
|
MPa | 300 |
|
Young's modulus
|
GPa | 395 |
|
Vickers hardness
|
(HU.5kgf) Gpa | 17.7 |
|
Fracture toughness
|
MPa·m1/2 | 4.0 |
|
Coefficient of thermal expansion
|
(20-900 )X10-6/K |
8.0 |
|
Thermal conductivity
|
(20) W/mk |
33.5 |
|
Thermal Shock resistance
|
( T) |
200 |
|
Max. service temperature
|
|
1800 |
|
Electrical conductivity
|
(20-100)  ·cm |
1017 |
|
Dielectric constant
|
(20,10GHz) |
10 |
|
tan
 |
(20,10GHz)X10-4 |
1.0 |
|
Total translucency
|
% | 96 |
|
Linear translucency
|
% | 40 |
