Оксид алюминия Сапфир
Сапфир хорошо известен своей прочностью. Чрезвычайная твердость, высокая прочность и трещиностойкость делают его отличным выбором материала для высокопроизводительной оптики.
Наша компания выращивает кристаллы методом горизонтально направленной кристаллизации со следующими размерами 300x220x25 мм.
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Main properties |
|
|
Chemical formula |
Al2O3 |
|
Crystal class |
Hexagonal system, rhomboidal class 3m |
|
Lattice constants, A |
a=4.785, c=12.991 |
|
Density, g/cm3 |
3.98 |
|
Melting point, °K |
2303 |
| Hardness |
Knoop(daN/mm2): 1800 parallel to C-axis, 2200 perpendicular to C-axis, Mohs: 9 |
|
Optical transmission range, µm |
0.17 - 5.5 |
| Refractive index at 0.532 µm |
n0=1.7717, ne=1.76355 |
|
Water absorption |
nil |
|
Young Modulus, Gpa |
345 |
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Shear Modulus, Gpa |
145 |
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Bulk Modulus, Gpa |
240 |
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Bending Modulus (Modulus of Rupture), Mpa |
420 at 20°C, 280 at 500°C |
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Elastic Coefficient |
C11=496, C12=164, C13=115, C33=498, C44=148 |
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Poisson ratio |
0.25-0.30 |
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Friction Coefficient |
0.15 on steel, 0.10 on sapphire |
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Tensile strength, MPa |
400 at 25°, 275 at 500°, 345 at 1000° |
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Flexural strength, daN/mm2 |
35 to 39 |
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Compressive strength, GPa |
2.0 |
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Young’s modulus E, daN/mm2 |
3.6 x 104 do 4.4 x 104 |
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Specific heat, J/(kg x K) |
105 at 91°K, 761 at 291°K |
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Thermal coefficient of linear expansion, K-1,at 323K |
6.66 x 10-6 parallel to optical axis, 5 x 10-6 perpendicular to optical axis |
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Thermal conductivity, W/(m x K) at 300K |
23.1 parallel to optical axis, 25.2 perpendicular to optical axis |
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Resistivity, Ohm x cm |
1016 (25°), 1011 (500°), 106 (1000°) |
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Dielectric constant |
1.5 (103 - 109 Hz, 25°) parallel to C-axis, 9.3 (103 - 109 Hz, 25°) perpendicular to C-axis |
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Dielectric strength, V/cm |
4 x 105 |
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Loss tangent |
1 x 10-4 |
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Solubility |
|
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- in water |
insoluble |
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- in HNO3,H2SO4, HCl, HF |
insoluble to 300 °C |
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- in alcalis |
insoluble to 800 °C |
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- in melts of metals Mg, Al, Cr, Co, Ni, Na, K, Bi, Zn, Cs |
insoluble to 800-1000 ° C |
|
g -radiation stability |
No change in transmission above 2.5 mm after exposure to 107 Rads. No visible coloration after exposure to 108 Rads/hr for 60 minutes at - 195°C |
|
Proton radiation stability |
No change in transmission below 0.3 µm after exposure to 1012 proton/cm2 total dose |
|
Chemical resistance |
Sapphire is highly inert and resistant to attack in most process environments including hydrofluoric acid and the fluorine plasma applications commonly found in semiconductor wafer processing (NF3, CF4) |
