Aluminium Oxide
Al2O3
|
Chemical name
Aluminium Oxide |
|
Mineral name
Sapphire, Corundum |
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Chemical formula
Al2O3 |
|
Melting point [°C]
2072 |
|
Crystal system
hexagonal, rhomboedric |
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Unit cell
a [Å]:4.758 b [Å]:4.758 c [Å]:12.991; a : c = 1 : 2.734 |
|
Molecular weight [g/mol]
101.96 |
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Twinning
twinfree |
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Mohs hardness
9 |
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Density [g/cm3]
3.95 |
|
Color
colourless |
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Refractive Index
nd=1.8336 (at 265 nm); nd = 1.58638 (at 5.6 mm) |
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Piezoelectric crystals
|
|
Thermal expansation coefficient [(10^(-5))/K]
0.54 || c-axis RT; 6.2 ^c-axis RT |
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Crystal growth method
Czochralski, HEM, Verneuil |
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Crystal growth orientation
(0001), (1102), (1012), (1010) |
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Maximum size
7 inch in diameter |
|
Variations
doped crystals (Fe, Nb, Ti, W, Ta, V, Cr), other dopands on request |
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Dielectric constant
9.4 || c-axis RT; 11.5 ^c-axis RT |
|
Dielectric loss tangent (10 GHz)
3.0*10^(-5) || c-axis RT; 8.6*10^(-5) ^c-axis RT |
|
Specific resistivity [W/cm]
10^16 |
|
Transmission range
0.2 - 6.0 mm |
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Orientation
(0001), (1102), (1012), (1010) |
|
Dispersion
0.011 |
