Orthodontics Sapphire Bracket Sapphire(Al203)property list
Molecular formula |
Al203 |
Density |
3.95-4.1g/cm ³ |
Crystalstructure |
Hexagonal crystal |
Lattice constant |
a =4.785A,c=12.991A |
Mohs hardness |
9(below the diamond:10) |
Melting point |
2045°C |
Boiling point |
3000°C |
Thermal expansivity |
5.8×10-6/K |
Specific heat |
0.418W.s/g/k |
Thermal conductivity |
25.12W/m/k(@100°C) |
Refractive index |
no=1.768 ne=1.760 |
dn/dt |
13×10-6/K(@633nm) |
Light penetration |
T≈80%(0.3~5μm) |
Permittivity |
11.5(//c),9.3(丄c) |