Orthodontics Sapphire Bracket
Orthodontics Sapphire Bracket Sapphire（Al203）property listMolecular formulaAl203Density 3.95-4.1g/cm ³CrystalstructureHexagonal crystalLattice constanta =4.785A,Website:http://www.ceramic-metal-parts.com,c=12.991AMohs hardness9（below the diamond：10）Melting point2045°CBoiling point3000°CThermal expansivity5.8×10-6/KSpecific heat0.418W.s/g/kThermal conductivity25.12W/m/k(@100°C)Refractive indexno=1.768 ne=1.760dn/dt13×10-6/K(@633nm)Light penetrationT≈80% （0.3~5μm）Permittivity11.5（//c）,9.3(丄c)
