SAPPHAL High-Purity Translucent Alumina Ceramics

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.

Image of SAPPHAL High-Purity Translucent Alumina Ceramics
SAPPHAL High-Purity Translucent Alumina Ceramics

Image of Crystal organization of SAPPHAL
Crystal organization of SAPPHAL

Fluorine Plasma Corrosion Test

Image of Fluorine Plasma Corrosion Test

You can see that other alumina ceramics in comparison with SAPPHAL have etched holes and that numerous particles have been generated.

Comparison of Impurity Content

Sapphal is effective in preventing alkali and metal contamination.

Image of Comparison of Impurity Content

SAPPHAL's Properties (Typical Data)

Alumina content
% 99.97
Bulk density
g/cm3 3.99
Absorption rate
% 0
Average crystal diameter
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
(20-900degrees)X10-6/K 8.0
Thermal conductivity
(20degrees) W/mk 33.5
Thermal Shock resistance
(deltaT)degrees 200
Max. service temperature
degrees 1800
Electrical conductivity
(20-100degrees) omega·cm 1017
Dielectric constant
(20degrees,10GHz) 10
(20degree,10GHz)X10-4 1.0
Total translucency
% 96
Linear translucency
% 40

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