Physical Properties of Sapphire

Crystal Structure

Hexagonal.   a =4.758 ?   c= 12.992 ?

Crystallographic D spacing

(1120 ) - a plane:  2.379 ?                (1102) - r plane:  1.740 ?

(1010) - m plane:  1.375 ?                (1123) - n plane: 1.147 ?ˉ

(0001) - c plane:   2.165 ?                (1011) - s plane:  1.961 ?

Crystal Purity

> 99.99%

Melt Point

2040 ^oC        

Density

3.98  g/cm³  

Hardness

9 ( mohs)

Thermal Expansion

 7.5  (x10^-6/ ^oC)

Specific Heat

0.10  ( cal / ^oC)

Thermal Conductivity,

46.06 @ 0 ^oC     25.12 @ 100 ^oC,     12.56 @ 400 ^oC        ( W/(m.K) )

Dielectric Constant

~ 9.4 @300K  at A axis    ~ 11.58@ 300K at C axis

Loss Tangent at 10 GHz

< 2x10^-5  at A axis ,       <5 x10^-5  at C axis

Standard Products

As - grown boules

 ori.± 0.5^o

3" dia x 50 ~ 70 mm length

2" dia x 50 ~ 70 mm length

30 mm dia  x 150 mm  length

As-cut blanks

ori.± 0.5^o

2" dia x 0.7 mm thickness

1" dia x 0.7 mm thickness

Epi -polished substrates

C, R, A plane: ori.± 0.5^o

1 or 2 sides polished

Ra< 10 ?

3" dia. x 0.5 mm  

2" dia. x 0.33 mm,   2"dia x 0.5 mm

1" dia  x 0.5 mm

0.5" x 0.5" x 0.5 mm

10x10x0.5 mm