Product Description
The Kyropoulos process (KY process) for sapphire crystal growth is currently used by many companies in China to produce sapphire for the electronics and optics industries.
High-purity, aluminum oxide is melted in a crucible at over 2100 degrees Celsius. Typically the crucible is made of tungsten or molybdenum. A precisely oriented seed crystal is dipped into the molten alumina. The seed crystal is slowly pulled upwards and may be rotated simultaneously. By precisely controlling the temperature gradients, rate of pulling and rate of temperature decrease, it is possible to produce a large, single-crystal, roughly cylindrical ingot from the melt.
After single crystal sapphire boules are grown, they are core-drilled into cylindrical rods, The rods are sliced up into the
desired window thickness and finally polished to the desired surface finish.
desired window thickness and finally polished to the desired surface finish.
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General
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Chemical Formula
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AL2O3
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Crystal Structure
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Hexagonal System (kh o 1)
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Unit Cell Dimension
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a=4.758 A,A c=12.991 A,c:a=2.730
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Physical
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Metric
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English (Imperial)
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Density
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3.98 g/cc
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0.144 lb/in3
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Hardness
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1525-2000 Knoop, 9 moh’s
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3700 F
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Melting Point
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2310 K (2040 ℃)
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Structure
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Tensile Strength (20 ℃)
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400 MPa
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58000 psi (design min.)
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Tensile Strength (500 ℃)
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275 MPa
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40000 psi (design min.)
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Tensile Strength (1000 ℃)
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355 MPa
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52000 psi (design min.)
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Flexural Strength
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480-895 MPa
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70000-130000 psi
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Compression Strength
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2.0 GPa (ultimate)
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300000 psi (u;timate)
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Application of Sapphire Wafer
Synthetic sapphire (sometimes referred to as sapphire glass) is commonly used as a window material, because it is both highly transparent to wavelengths of light between 150 nm (UV) and 5500 nm (IR) (the visible spectrum extends about 380 nm to 750 nm, and extraordinarily scratch-resistant. The key benefits of sapphire windows are:
* Very wide optical transmission band from UV to near-infrared
* Significantly stronger than other optical materials or glass windows
* Highly resistant to scratching and abrasion (9 on the Mohs scale of mineral hardness scale, the 3rd hardest natural substance next to moissanite and diamonds)
* Extremely high melting temperature (2030 °C)
* Very wide optical transmission band from UV to near-infrared
* Significantly stronger than other optical materials or glass windows
* Highly resistant to scratching and abrasion (9 on the Mohs scale of mineral hardness scale, the 3rd hardest natural substance next to moissanite and diamonds)
* Extremely high melting temperature (2030 °C)
