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

0.17- 5.5 [µm]

Refractive index at 0.532

n0=1.7717, ne=1.76355 [µm]

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

Tensile strength,  MPa

400 at 25°, 275 at 500°, 345 at 1000°

Flexural strength, daN/mm2

35 to 39

Compressive  strength, GPa

2

Young's modulus E, daN/mm2

3.6 X 104 to 4.4 X 104

Specific  heat, J/(kg x K)

105 at 91°K, 761 at 291 °K

Thermal coefficient of linear expansion, K-1, at323K

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

Resistivity, Ohm x cm

1016 (25°), 1011 (500°), 106 (1000°)

Dielectric constant

11.5 (103- 109 Hz, 25°) parallel to C-axis, 9.3 (103- 109 Hz, 25°) perpendicular  to C-axis

Dielectric strength,  V/cm

4x 105

Loss tangent

1 X 10-4

Solubility

-in water

-in HN03,H2S04, HCI, HF

-in alcalis

-in melts of metals Mg, AI, Cr, Co, Ni, Na, K, Bi, Zn, Cs

insoluble

insoluble to 300 °C

insoluble to 800 °C

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 m 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

Wsp. załamania światła:

4,0026 dla 11 μm

Straty rozproszeniowe:

53% dla 11 μm (dwie powierzchnie)

Współczynnik pochłaniania:

<0,027 cm-1 dla 10.6 μm

dn/dT:

396 x 10-6 /°C 

dn/dμ = 0:

prawie stały

Gęstość:

5,33 g/cm3

Temperatura topnienia:

936 °C 

Przewodność cieplna:

58,61 W m-1 K-1 dla 293K

Rozszerzalność cieplna:

6,1 x 10-6/°C dla 298K 

Twardość:

Knoop 780

Ciepło właściwe:

310 J Kg-1 K-1 

Stała dielektryczna:

16,6 dla 9,37 GHz przy 300K

Moduł Young'a (E):

102,7 GPa 

Moduł Shear'a (G):

67 GPa 

Moduł Bulk'a (K):

77,2 GPa 

Współczynnik elastyczności:

C11=129; C12=48,3; C44=67,1 

Pozorna granica sprężystości:

89,6 MPa (13000 psi)

Współczynnik Poisson'a:

0,28

Rozpuszczalność:

Nierozpuszczalny w wodzie

Masa cząsteczkowa:

72,59

Klasa / Struktura:

Sześcienny diament, Fd3m