|
Sapphires and rubies have excellent resistance against abrasion, heat,
and chemicals as well as high thermal conductivity and insulating
capabilities. Polishing a sapphire or ruby yields ideal plane smoothness and precision.
·Features of white sapphires
| Chemical composition
|
AI2O3
|
| Crystal system
|
Hexagonal system
|
| Hardness
|
Mohs hardness 9
Knoop hardness perpendicular to the c axis 1.525 to 1.660 kgf/mm2
Knoop hardness parallel to the c axis 1.670 to 2.000 kgf/mm2
|
| Specific gravity
|
3.98
|
| Fusing temperature
|
2.040°C
|
| Thermal conductivity
|
0.1 cal/cm sec°C at 20°C
0.06 cal/cm sec°C at 100°C
|
|
Thermal expansion coefficient
(mean value from 25°C)
|
Perpendicular to the c axis Parallel to the c axis
50°C 50 x 10-7cm/cm°C 67 x 10-7cm/cm°C
500°C 50 x 77-7cm/cm°C 67 x 83-7cm/cm°C
1,000°C 50 x 83-7cm/cm°C 67 x 90-7cm/cm°C
|
| Refractive index[24°C]
|
6563A nc perpendicular to the c axis 1,765 parallel to the c axis 1,757
5893A no perpendicular to the c axis 1,768 parallel to the c axis 1,760
4861A nf perpendicular to the c axis 1,775 parallel to the c axis 1,767
|
| Dielectric constant
|
9.0 at 105 Hz and 11.0 at 10 GHz on the c axis
|
| Threshold voltage
|
480,000V/cm
|
| Dielectric strength
|
20,800kg/cm2
|
| Destruction coefficient
|
5,000 to 7,000kg/cm2
|
| Young's modulus
|
3.5 to 3.8 x 106kg/cm2
|
|
Volume-specific resistance
|
500°C 1011Ωcm
1,000°C 108Ωcm
1,500°C 104Ωcm
|
·Features of rubies
| Chemical composition
|
Cr:AI2O3
|
| Crystal system
|
Hexagonal system
|
| Hardness
|
Mohs hardness 9
Knoop hardness perpendicular to the c axis 1.525 to 1.660 kgf/mm2
Knoop hardness parallel to the c axis 1.670 to 2.000 kgf/mm2
|
| Fusing temperature
|
2.040°C
|
| Thermal conductivity
|
0.1 cal/cm sec°C at 20°C
0.06 cal/cm sec°C at 100°C
|
|
Thermal expansion coefficient
|
Perpendicular to the c axis Parallel to the c axis
50°C 50 x 70-7cm/cm°C 67 x 10-7cm/cm°C
500°C 50 x 77-7cm/cm°C 67 x 83-7cm/cm°C
1,000°C 50 x 83-7cm/cm°C 67 x 90-7cm/cm°C
|
| Threshold voltage
|
480,000V/cm
|
| Dielectric strength
|
20,800kg/cm2
|
| Destruction coefficient
|
5,000 to 7,000kg/cm2
|
·Items handled
-Rough white sapphires
-Rough rubies
-Sapphire plates for watches
-Sapphire bearings
·Applications
-Sapphire crystals for high-grade watch components
-Jewel bearings for watthour meters
-Jewel bearings for waterworks meters
-Micro surgery scalpels
-Bonding capillaries
-Dispenser nozzles
-Check valve plungers for analytic equipment
-Ink jet nozzles
-Ruby balls
-Other measurement components
|
