The sapphire is a single crystal rhombohedral struture made of Aluminum Oxide (Al203).
The synthetic industrial sapphire/ruby is obtained from the controlled fusion of this very fine powder (Al203) in special ovens at a temperature of 2040 °C.
When heated to this temperature the powder melts and can then be formed into a single crystal (boule) of such extreme hardness ( 9 Mohs st ), that it is second
only to diamond and which can be precision fabricated to meet all possible needs.
Several crystal growth methods exist, each having differing results in quality, size and costs.
This material has exactly the same chemical and physical properties as the best quality aluminum ceramics, for example in resistance to abrasion, corrosion and high temperature.
Whatsmore the single crystal structure allows for a very high grade of finish and exact precision fabrication even at the smallest dimensions.
The synthetic industrial ruby is made when this very same material is doped with a small concentrate of chromium (Cr), typically in the range of 0.05%, which produces shades of red without effecting the mechanical properties in any way.
Take a look at the table for more technical information.
|Formula||–||Al2O3 (Ruby Al2O3/Cr2O3)|
|Composition||Gew.%||99.99 (Ruby 99/1)|
|Fracture toughness K1c||MN/m3_2||1|
|Modulus of elasticity||Gpa||430|
|Coefficient of thermal expansion||10-6/K||5,4|
|Dielectric strength||Ac V/mil||1200|
|Dielectric constant||@ 1 Mhz||9.3-11.5|
|Transmission band||µm||0.3-5.0 wavelength (>80% transmission)|
|Maximum use temperature in air||°C||1800|