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Sapphire (Al2O3)

♦ Sapphire (Al2O3) Data Sheet   ♦ Sapphire (Al2O3) MSDS

Sapphire (Al2O3) Rough Guide

Sapphire is used for its extreme toughness and strength. Sapphire is a very useful optical window material for use in the UV, visible, and near infra-red.

Transmission Range:   0.17 to 5.5 μm
Refractive Index:  No 1.75449; Ne 1.74663 at 1.06 μm (1)
Reflection Loss:   14% at 1.06 μm
Absorption Coefficient:  0.3 x 10-3 cm-1 at 2.4 μm (2)
Reststrahlen Peak:  13.5 μm
dn/dT:  13.1 x 10-6 at 0.546 μm (3)
dn/dμ = 0:  1.5 μm
Density:  3.97 g/cc
Melting Point:  2040°C
Thermal Conductivity:  27.21 W m-1 K-1 at 300K
Thermal Expansion:  5.6 (para) & 5.0 (perp) x 10-6/K *
Hardness:  Knoop 2000 with 2000g indenter
Specific Heat Capacity:  763 J Kg-1 K-1 at 293K (4)
Dielectric Constant:  11.5 (para) 9.4 (perp) at 1MHz
Youngs Modulus (E):  335 GPa
Shear Modulus (G):  148.1 GPa
Bulk Modulus (K):  240 GPa
Elastic Coefficients:  C11=496 C12=164 C13=115 C33=498 C44=148
Apparent Elastic Limit:  300 MPa (45,000 psi)
Poisson Ratio:  0.25
Solubility:  98 x 10-6 g/100g water
Molecular Weight:  101.96
Class/Structure:  Trigonal (hex), R3c

 

To download this data or our MSDS safety data sheet as a pdf, please click on the links at the top of the page.  To expand the transmission graphs, please click on the image.

Click to access current Sapphire Stock Windows
Click to access current Sapphire Stock Prisms

µm   NoNeµm   NoNeµm   NoNe
0.193    1.9288 1.9174 0.213    1.8890 1.8784 0.222    1.8754 1.8650
0.226    1.8702 1.8599 0.244    1.8506 1.8407 0.248    1.8470 1.8372
0.257    1.8393 1.8297 0.266    1.8330 1.8236 0.280    1.8244 1.8151
0.308    1.8110 1.8020 0.325    1.8047 1.7958 0.337    1.8001 1.7921
0.351    1.7969 1.7882 0.355    1.7960 1.7883 0.442    1.7804 1.7721
0.458    1.7784 1.7702 0.488    1.7753 1.7671 0.515    1.7730 1.7649
0.532    1.7717 1.7636 0.590    1.7680 1.7600 0.633    1.7659 1.7579
0.670    1.7643 1.7563 0.694    1.7634 1.7554 0.755    1.7614 1.7535
0.780    1.7607 1.7527 0.800    1.7601 1.7522 0.820    1.7596 1.7517
0.980    1.7561 1.7482 1.064    1.7545 1.7466 1.320    1.7501 1.7423
1.550    1.7462 1.7384 2.010    1.7375 1.7297 2.249    1.7323 1.7243
2.703    1.719 1.711 2.941    1.712 1.711 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

Sapphire is grown by a variety of methods. Verneuil and Czochralski methods are usual for standard grade Sapphire material. Higher quality Sapphire, particularly for electronic substrates is manufactured by Kyropulos growth and this can be very pure with excellent UV transmission. Large thin sheets of Sapphire can be made by ribbon growth. Sapphire is slightly birefringent, general purpose IR windows are usually cut in a random way from crystal but for specific applications where the birefringence is an issue, an orientation is selected. Usually this is with the optic axis at 90 degrees to the surface plane and is known as "zero degree" material. Synthetic optical sapphire has no colouration.
* Note that all manufacturers seem to disagree on the actual figures for thermal expansion!
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V3, ISBN 0-12-544423-0
(2) Harrington et al, Appl.Opt. V15, 1953-1959 (1976)
(3) Malitson, J.Opt.Soc.Am., V52, 1377- 1379 (1962)
(4) D. A. Ditmars, et. al., J. Res. Nat. Bur. Stand., 87, (2), 159-163 (1982).

Data provided is extracted from our technical handbook of materials. While every attempt has been made to verify the source of the information, Crystran Ltd accept no responsibility for accuracy of data.