Si3N4
Silicon Nitride:
The most widely used type of ceramic due to very high
resistance to wear and abrasion in general. It has a
micro - structure specially designed for applications
subject to great stress. It does not require lubrication,
it is resistant to corrosion, anti magnetic and electrically
insulating, and it continues to be efficient at high
temperatures up to +1400 oC. It combines extreme hardness
with a high precision ball. Si3N4 balls are widely used
in high precision bearings in the airspace industry,
for machine tools, measurement instruments, mechanical
centrifuges, radar and missiles, pumps and compressors.
| PHYSICAL
PROPERTIES |
| Structure |
Multi-Crystal |
| Chemical
Formula |
Si3N4 |
| Purity
% |
95,00 |
| Density
g/cm |
3,20 |
| Operating
Temperature °C |
1100 |
| Melting Point |
1900° Ñ |
| Softening Point |
100° Ñ |
Specific Heat
at 25° C
(cal/g/° C)
Thermal Conductivity |
0,17
29 W/m° K |
| MECHANICAL
PROPERTIES |
| Vickers
Hv10 Hardness (N/mm2) |
24000 |
| Modulus
of Elasticity (N/mm2) |
3,1õ105 |
| Breaking
Modulus at 25° C (N/mm2) |
700 |
| Compressive
Strength at 25° C (N/mm2) |
2500 |
Top
Al2O3
99, 55% ALUMINA (ALUMINA OXIDE):
The material has a multi-crystal structure and excellent
resistance to abrasion and high temperatures. It is
resistant to most corrosive agents, but it is not
recommended for use in contact with hydrochloric and
hydrofluoric acid or strong alcaline solutions. Al2O3
balls are used in valves, pumps and ball bearings.
| PHYSICAL
PROPERTIES |
| Structure |
Multi-Crystal |
| Chemical
Formula |
ÀL2Î3 |
| Purity
% |
99,8 |
| Density
g/cm |
3,90 |
| Operating
Temperature °C |
1800 |
| Melting
Point |
2050° C |
| Softening
Point |
1725° Ñ |
Specific
Heat at 25° C
(cal/g/° C)
Thermal Conductivity |
0,25
29 W/m° K |
| MECHANICAL
PROPERTIES |
| Vickers
Hv10 Hardness (N/mm2) |
16500 |
| Modulus
of Elasticity (N/mm2) |
3,5õ105 |
| Breaking
Modulus at 25° C (N/mm2) |
470 |
| Compressive
Strength at 25° C (N/mm2) |
2354 |
Top
ZrO2 ZIRCONIUM OXIDE:
The material, compared has a high degree of compactness
and considerable flexural strength, which makes it
very reliable. It also has a low modulus of elasticity,
close to that of steel, together with an extraordinarily
low thermal conductivity.
| PHYSICAL
PROPERTIES |
| Structure |
Multi-Crystal |
| Chemical
Formula |
ZrO2 |
| Purity
% |
97,00 |
| Density
g/cm |
5,50 |
| Operating
Temperature °C |
1000 |
| Melting
Point |
|
| Softening
Point |
|
Specific
Heat at 25° C
(cal/g/° C)
Thermal Conductivity |
9
W/m° K |
| MECHANICAL
PROPERTIES |
| Vickers
Hv10 Hardness (N/mm2) |
20000 |
| Modulus
of Elasticity (N/mm2) |
2õ105 |
| Breaking
Modulus at 25° C (N/mm2) |
600 |
| Compressive
Strength at 25° C (N/mm2) |
2100 |
Top
Al2O3
99, 99% RUBY:
This material has a non porous single crystal structure
used where particular hardness and extreme resistance
to wear are required together with a low specific
weight and properties of chemical inertia. The material
consists of pure aluminium oxide with a small percentage
of chromo oxide which gives it its characteristic
red colour, which is the most visible feature of these
balls in many applications as measurement and control
insruments, valves and pumps.
| PHYSICAL
PROPERTIES |
| Structure |
Single Crystal |
| Chemical
Formula |
ÀL2Î3 |
| Purity
% |
99,99 |
| Density
g/cm |
3,99 |
| Operating
Temperature °C |
|
| Melting
Point |
2050° C |
| Softening
Point |
1800° C |
Specific
Heat at 25° C
(cal/g/° C)
Thermal Conductivity |
0,18
36 W/m° K |
| MECHANICAL
PROPERTIES |
| Vickers
Hv10 Hardness (N/mm2) |
17000 |
| Modulus
of Elasticity (N/mm2) |
4,3õ105 |
| Breaking
Modulus at 25° C (N/mm2) |
392 |
| Compressive
Strength at 25° C (N/mm2) |
2060 |
Top
Al2O3
99, 99% SAPPHIRE:
This material has a single crystal structure and unlike
ruby is transparent. Because of its optical properties
and high refraction index. Balls made of this material
are currently used as chemically inert lenses.
| PHYSICAL
PROPERTIES |
| Structure |
Single Crystal |
| Chemical
Formula |
ÀL2Î3 |
| Purity
% |
99,99 |
| Density
g/cm |
3,99 |
| Operating
Temperature °C |
|
| Melting
Point |
2050° C |
| Softening
Point |
1800° C |
Specific
Heat at 25° C
(cal/g/° C)
Thermal Conductivity |
0,18
36 W/m° K |
| MECHANICAL
PROPERTIES |
| Vickers
Hv10 Hardness (N/mm2) |
17000 |
| Modulus
of Elasticity (N/mm2) |
4,3õ105 |
| Breaking
Modulus at 25° C (N/mm2) |
392 |
| Compressive
Strength at 25° C (N/mm2) |
2060 |
Top
CHEMICAL RESISTANCE
Sapphire / Ruby:
inert to most acids at very high temperatures.
Alumina (Oxide):
inert to most acids, but not recommended in environments
with hydrochloric or hydrofluoric acids or strong
alkaline solutions.
Silicon Nitride:
inert to most acids
Zirconium Oxide:
inert except to hydrofluoric acid and strong concentrations
of sulphuric acid.
