SAPPHIRE BALLS

High purity monocrystalline aluminum oxide balls, they are transparent and provide high hardness, wear, temperature and corrosion resistance.
Applications
Special bearings, chemical, medical ans check valves, flowmeters, pens and styli tips, measurement instruments, bar code readers, fiber optical connectors.
Commercial name
Other name
Formula
Oxide %
Monocrystalline Aluminum Trioxide
Sapphire
Al2O3
99.90-99.99
Physical / mechanical / thermal / electric / magnetic properties
Property
Symbol
U.o.M.
Type
Notes
Values
Density
δ
[g/cm3]
Physical
Room temp.
3.98
Young's modulus
E
[GPa]
Mechanical
-
415
Friction coefficient
µ
-
Mechanical
Room temp.
0.15
Specific heat
c
[J/kg-K]
Thermal
Room temp.
750
Coefficient of linear thermal expansion
α
[10^-6/ºC]
Thermal
(ΔT=0-100°C)
6.0
Thermal conductivity
λ
[W/(m·K)]
Thermal
Room temp.
40.0
Volume resistivity
ρ
[Ω*m]
Electric
-
> 10^14
Relative magnetic permeability
µ
-
Magnetic
Diamagnetic
<~1
Technical data
Property
Type
U.o.M.
Values
U.o.M.
Values
Hardness
Mechanical
[HV]
1600 - 2300
-
-
Ultimate compressive strength
Mechanical
[MPa]
2000 - 2100
[psix10^3]
290 - 304
Service temperature
Thermal
[ºC]
-196 / 1800
[ºF]
-320.8 / 3272
Range
Diameters (min/max)
U.o.M.
Diameters (min/max)
U.o.M.
Precision grades
0.200 - 20.000
[mm]
1/128 - 25/32
["]
G3-5-6-10-25
Corrosion Resistance
Sapphire balls provide excellent corrosion resistance both in acid and basic environments, even in severe conditions., better than ruby balls. They are attacked only by melt substanbces containing Li, B, F, Na and K elements.
Revision n.7