Ceramic bearings

Dr. Dmitri Kopeliovich

• Features of ceramic bearings
• Hybrid ceramic bearings
• Full ceramic bearings
• Applications of ceramic bearings

• Low weight (about 0.4 of steel bearings}.
• Exceptional corrosion resistance.
• High rotation speed and acceleration {centrifugal forces are low due to low weights of the balls/rollers and rings}.
• High thermal resistance. Maximum operating temperature is 1800°F (982°C).
• Excellent wear resistance.
• Long service life.
• Excellent insulating properties.
• High dimension stability (coefficient of thermal expansion is about 0.25 of steel).
• High hardness (about 1500 HV).
• High stiffness (resistance to elastic deformation) due to high modulus of elasticity.
• Non-magnetic.
• Low coefficient of friction due to good surface quality.
• Good Seizure resistance (compatibility) in vacuum.
• Greater accuracies.

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Hybrid ceramic bearings consist of ceramic balls (or rollers) and steel races, cages/retainers and seals/shields.

The balls/rollers may be made of the following ceramics:

• Silicon Nitride (Si₃N₄)
• Zirconia ceramics (ZrO₂)
• Alumina ceramics (Al₂O₃)

The steel parts are made of Chrome steel (eg. AISI 52100) or Stainless steel AISI 316.

Hybrid ceramic bearings are mainly used in high speed and insulating applications.
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Full ceramic bearings are made only of ceramics (contain no steel parts).

The following ceramics are used for manufacturing full ceramic bearings:

• Silicon Nitride (Si₃N₄)
• Zirconia ceramics (ZrO₂)
• Alumina ceramics (Al₂O₃)

Full ceramic bearings are widely used in harsh environments (chemicals, vacuum, high temperature, radiation).

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• Pumps for domestic hot water circulators, dishwashers and washing machines.
• Industrial pumps for pumping water from deep wells.
• Submersible pumps for aquariums and garden ponds.
• Automotive water pumps.
• Aircraft valves, transmissions and gearboxes.
• Gas turbine mainshaft.
• Dental handpiece turbines.
• Semiconductors processing equipment.
• Food processing equipment.
• High speed spindles.
• Electroplating equipment.
• Chemical processing equipment.
• Furnaces for heat treatment.
• Aircraft engines.
• Vacuum apparatus.

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• Materials for joint prostheses
• Ceramics in combustion engines
• Tribological properties and applications of alumina
• Thermal barrier coatings
• Tribology of ceramics
• Engine bearings

to Ceramics
to Applications of ceramics