The hardest of the oxide crystals, sapphire retains its high strength at high temperatures, has good thermal properties and excellent transparency. It has high transmittance from 1.5 μm to 6.0 μm in the middle infrared. The other hand, it is chemically resistant to common acids and alkali at temperatures up to 1000 °C as well as to HF below 300 °C. These properties encourage its wide use in hostile environments where optical transmission in the range from the vacuum ultraviolet to the near infrared is required.
Physical and Optical Properties:
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Crystal Type
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Hexagonal
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|
Lattice Parameter
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a=4.75Å, c=12.97Å
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|
Transmission Band
|
0.15-6 μm
|
|
Melting Point
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2040 ℃
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|
Thermal Conductivity
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4W/cm/℃
|
|
Refractive Index
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1.623 at 5μm
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|
Specific Heat
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0.18cal/g/℃
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|
Thermal Expansion
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7.7x10-6/℃
|
|
Mohs Hardness
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9
|
|
Density
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3.98g/cm3
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Specifications:
|
Material
|
Sapphire
|
|
Dimension Tolerance
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+0.0, -0.1mm
|
|
Thickness Tolerance
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±0.1mm
|
|
Surface Quality
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40/20
|
|
Clear Aperture
|
>90%
|
|
Flatness
|
λ/4@632.8nm
|
|
Parallelism
|
3'
|
|
Bevel
|
<0.25mm×45°
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|
Coating
|
According to Customer Request
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