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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

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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

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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

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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

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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

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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.

 
   
 
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