Technical Information Single Crystal Sapphire

Why choose Single Crystal Sapphire products?

Single crystal sapphire possesses excellent optical, physical and chemical properties. It is the hardest oxide crystals, and remains high strength and chemical resistance at high temperatures. It also features a wide transmission wavelength range, great electrical insulation, and good thermal conductivity at low temperatures.


Physical Properties of Sapphire

Chemical formula Al2O3(99.999%)
Crystal class Hexagonal system, rhomboidal class 3m
Lattice constants, A a=4.785, c=12.991
Density, g/cm3 3.98
Hardness 2000 with 2000 g identer
(Knoop)
9 (Mohs)
Optical transmission range, μm 0.17 - 5.5
Refractive index at 0.532 μm no=1.7717, ne=1.76355
Water absorption nil
Young Modulus, GPa 345
Shear Modulus, GPa 145
Bulk Modulus, GPa 240
Bending Modulus
(Modulus of Rupture), MPa
420 at 20 °C
280 at 500 °C
Elastic coefficient C11=496, C12=164, C13=115, C33=498, C44=148
Poisson ratio 0.25-0.30
Friction coefficient 0.15 on steel
0.10 on sapphire

Thermal Properties of Sapphire

Meling point, K 2303
Specific heat, J/(kg x K) 105 at 91K
761 at 291K
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
Thermal conductivity, W/(m x K) at 300K 23.1 parallel to optical axis
25.2 perpendicular to optical axis

Electrical Properties of Sapphire

Resistivity, Ohm x cm at 200-500 °C 1011 - 1016
Dielectric constant 10.0
Dielectric strength, V/cm 4 x 105
Loss tangent 1 x 10-4

Transmission spectrum of 2 mm-thick sapphire window


Sapphire Refractive Index vs Wavelength

l, mm
No
Ne
0.193
1.92879
1.91743
0.213
1.88903
1.87839
0.222
1.87540
1.86504
0.226
1.87017
1.85991
0.244
1.85059
1.84075
0.248
1.84696
1.83719
0.257
1.83932
1.82972
0.266
1.83304
1.82358
0.280
1.82437
1.81509
0.308
1.81096
1.80198
0.325
1.80467
1.79582
0.337
1.80082
1.79206
0.351
1.79693
1.78825
0.355
1.79598
1.78732
0.442
1.78038
1.77206
0.458
1.77843
1.77015
0.488
1.77530
1.76711
0.515
1.77304
1.76486
0.532
1.77170
1.76355
0.590
1.76804
1.75996
0.633
1.76590
1.75787
0.670
1.76433
1.75632
0.694
1.76341
1.75542
0.755
1.76141
1.75346
0.780
1.76068
1.75274
0.800
1.76013
1.7522
0.820
1.75961
1.75168
0.980
1.75607
1.74819
1.064
1.75449
1.74663
1.320
1.75009
1.74227
1.550
1.74618
1.73838
2.010
1.73748
1.72973
2.249
1.73232
1.72432
2.703
1.719
1.711
2.941
1.712
1.704
3.333
1.701
1.693
3.704
1.687
1.679
4.000
1.674
1.666
4.348
1.658
1.65
4.762
1.636
1.628
5.000
1.623
1.615
5.263
1.607
1.599
Network Solution Security Seal