Aluminium Oxide
ά? -Al2O3
 

Aluminium oxid: Al2O3-Cr, 
Al2O3-Flux, Al2O3-Cr Flux

Aluminium oxid: Al2O3 Korundum 
and Ruby-Crystals

Aluminium oxid: Al2O3 : Cr
Ruby rod

 
   

Aluminium oxid Al2O3

Aluminium oxid Al2O3

 

 
Aluminium Oxide6  
Aluminium Oxide7 Aluminium Oxide8

Aluminium Oxide9

 

Crystal properties

Crystal growth method

Czochralski, HEM,Verneuil

Crystal growth orientation

(0 001),(1102),(1012),(1010)

Maximum size

7 inch diameter

Variations

Doped crystals (Fe, Nb, Ti, W,Ta,V,Cr)
Other dopands on request 

Crystallographic properties

Hexagonal / Rhombohedric

Crystallographic structure

a = 4.77 A
c = 13.04 A
a : c = 1 : 2.734

a =   4.758 Å
c = 12.991 Å

Mineralogical synonyms

 Sapphire, Corundum

Twinning structure

Twinfree

Colour

 Colourless

Density

3.98 g/cm3

Melting point

2052  °C

Hardnes

9   (Mohs)

Thermal  expansion coefficient

5.4 * 10_6 K_1 
6.2 * 10_6 K_1

|| c-axis
^ c-axis 

RT
RT

Dielectric  constant

9.4
11.5

| c-axis
^ c-axis

RT
RT

 

Physical properties cont.

Dielectric loss tangent (10GHz)

Aluminium Oxide10

 

3.0 * 10_5
8.6 * 10_5

| | c-axis
^ c-axis

RT
RT

Dielectric constant:

1016 W/cm

RT

 

Optical properties

Transmission range

0.2 to 6.0 mm

 

Refraction index:

nd = 1.8336 
nd = 1.58638 

at 265 nm
 at 5.6 mm

Dispersion

 0.011

 

 

Standard orientations

Aluminium Oxide11

(0001),(1102),(1012),(1010)

Other orientations on request

List of  Refractive index, ordinary ray at 24 °C (Al2O3)

Optical properties  refraction index Aluminium oxide

Wavelength (µm)

Refractive index 

0,28035

1,8243

0,289036

1,8195

0,29673

1,8159

0,30215

1,8135

0,31300

1,8091

0,33415

1,8018

0,34662

1,7981

0,36105

1,7945

0,36501

1,7936

0,39064

1,7883

0,40466

1,7858

0,43583

1,7812

0,54607

1,7708

0,57696

1,7688

0,57907

1,7687

0,64385

1,7655

0,70652

1,7630

0,85212

1,7588

0,89440

1,7579

1,01398

1,7555

1,12866

1,7534

1,36728

1,7494

1,39506

1,7489

1,52952

1,7466

1,69320

1,7437

1,70913

1,7434

1.81307

1,7414

1.97010

1,7383

2,15260

1,7344

2,24929

1,7323

2,32542

1,7306

2,43740

1,7278

3,24320

1,7044

3,26660

1,7036

3,30300

1,7023

3,29300

1,7015

3,41880

1,6982

3,50780

1,6950

3,70000

1,6875

4,25800

1,6637

4,95400

1,6266

5,14560

1,6151

5,34900

1,6020

5,41900

1,5973

5,577

1,5864