Silicon nitride ceramic bearing balls are the core rolling elements of hybrid ceramic bearings (steel raceway rings + ceramic balls) and full ceramic bearings.
Compared with traditional bearing steel balls, silicon nitride ceramic balls feature low density (only 40% of steel), high hardness, high elastic modulus and low friction coefficient, as well as excellent corrosion resistance and electrical insulation performance.
Under harsh conditions such as high speed, high temperature, corrosion, non-lubrication and magnetic interference, silicon nitride ceramic balls can significantly improve the limiting speed, service life and reliability of bearings.
| Test item | Unit | Index range |
| Material | – | Si₃N₄ |
| Density | g/cm³ | 3.2 |
| Vickers Hardness (HV10) | kgf/mm² | 1400-1500 |
| Flexural Strength | MPa | ≥700 |
| Compressive Strength | MPa | ≥2800 |
| Fracture Toughness | MPa·m¹/² | ≥6.5 |
| Modulus of Elasticity | GPa | 310 |
| Poisson's Ratio | – | |
| Coefficient of Thermal Expansion (20–800°C) | ×10⁻⁶ /K | 3.2 |
| Thermal Conductivity | W/(m·K) | 20 |
| Recommended Maximum Operating Temperature (Air) | ℃ | 1200 |
| Magnetic Permeability | – | 0 (non-magnetic) |
| Nominal Diameter (mm) | Common Grades | Application |
| 1.588（1/16″） | G3、G5 | Miniature Bearings |
| 2.381（3/32″） | G3、G5 | Instrument Bearings |
| 3.175（1/8″） | G3、G5 | High-Speed Electric Spindles |
| 4.762（3/16″） | G5、G10 | Machine Tool Spindle Bearings |
| 6.350（1/4″） | G5、G10 | Automotive Hub Bearings |
| 7.938（5/16″） | G5、G10 | Industrial Pump Bearings |
| 9.525（3/8″） | G10、G16 | Large Motor Bearings |
| 12.700（1/2″） | G10、G16 | Wind Turbine Bearings |
| 15.875（5/8″） | G16 | Heavy-Duty Machinery Bearings |
| 19.050（3/4″） | G16 | Mining Equipment Bearings |
| 25.400（1″） | G16 | Special-Purpose Large Bearings |
Other imperial or metric sizes are available upon request.
| Grade | Ball Diameter Variation (Vdws) | Spherical Error (Spherical Deviation) | Surface Roughness (Ra) |
| G3 | ≤0.08 μm | ≤0.08 μm | ≤0.010 μm |
| G5 | ≤0.13 μm | ≤0.13 μm | ≤0.014 μm |
| G10 | ≤0.25 μm | ≤0.25 μm | ≤0.020 μm |
| G16 | ≤0.40 μm | ≤0.40 μm | ≤0.025 μm |
| G20 | ≤0.50 μm | ≤0.50 μm | ≤0.032 μm |
Note: Grades G3 to G5 are suitable for ultra-high-speed precision bearings; grades G10 to G16 are suitable for general-purpose industrial bearings; and grade G20 is used for low-precision applications.
1. Low density (3.20 g/cm³) and low centrifugal force significantly reduce the load exerted by the rolling elements on the rings during high-speed operation, allowing for higher maximum operating speeds (up to 1.5 times that of steel ball bearings).
2. Extremely high hardness (HV 1400–1500), excellent wear resistance, good dimensional stability, and high precision retention after long-term operation.
3. High elastic modulus (approx. 310 GPa), high rigidity, and minimal deformation, making it suitable for precision spindles requiring high rigidity.
4. Low coefficient of friction and good self-lubricating properties, allowing for short-term operation with minimal or no lubrication.
5. Low coefficient of thermal expansion (approx. 3.2×10⁻⁶ /K); minimal impact of operating temperature rise on bearing clearance; excellent thermal stability.
6. High-temperature resistance: Can operate stably for extended periods at temperatures below 800°C, far exceeding the limit of bearing steel (approximately 150°C).
7. Corrosion resistance: Resistant to acids, alkalis, seawater, and various chemical media; suitable for corrosive environments such as chemical pumps and marine applications.
8. Electrical insulation: Volume resistivity > 10¹⁴ Ω•cm; effectively prevents electro-erosion (spark erosion); suitable for applications such as variable-frequency motors and rail transit.
9. Non-magnetic: Does not interfere with magnetically sensitive equipment, making it suitable for medical or precision instruments such as MRI machines and magnetic levitation systems.
10. Long fatigue life: In hybrid ceramic bearings, the contact fatigue life of silicon nitride ceramic balls can be 3 to 5 times that of steel balls.
1. High-speed machine tool spindle bearings (electric spindles, engraving machine spindles).
2. Bearings for aerospace engine components and gyroscopes.
3. Automotive turbocharger bearings, wheel hub bearings, and drive motor bearings for new energy vehicles.
4. Wind turbine main shaft bearings and yaw bearings.
5. Bearings for chemical pumps, corrosion-resistant pumps, and seawater pumps.
6. Bearings for vacuum equipment (oil-free lubrication).
7. Bearings for rail transit traction motors (anti-electrical erosion).
8. Bearings for semiconductor equipment and precision instruments (non-magnetic, low-vibration).
9. Drive bearings for high-temperature furnaces and heat treatment equipment.
