Ceramic Bearings
Comparison between ceramic and metal bearings
Ceramic bearings boast a number of advantages over metal bearings:
- Extremely smooth running characteristics as result of very low friction
- Low-maintenance or zero-maintenance (media-lubrication or zero lubrication both possible)
- Excellent wear resistance and thus long service life
- Reduced weight (up to 60% less)
- Excellent chemical resistance (especially corrosion resistance & resistance to humidity)
- High hardness
- High stiffness
- Non-magnetic
- Excellent temperature stability
These properties open up a host of application possibilities in the following areas:
- Aerospace engineering
- Machinery and equipment
- Turbo pumps
- Chemicals industry (aggressive media)
- Metalwork industry (high operating temperatures)
- Pharmaceuticals industry
- Medical technology
- Food industry
- Precision Measurement Technology
- Semiconductor industry and biotechnology (e.g. clean room conditions do not allow for any contamination by lubricants)
Ball bearings are available either as hybrid bearings (steel rings and ceramic ball elements) or as full-ceramic bearings. Hybrid bearings easily substitute metal bearings, however, they do not show all the material advantages listed above. This is why full-ceramic bearings with rings and rolling elements (balls, cylinders, cones) are preferred for many applications. The main ceramic material used for our bearings is non-oxide ceramics (Si3N4). For specifics on the advantages of the different materials, see the data sheets.
| Materials Properties | Si3N4 | ZrO2 | AI2O3 | 100Cr6 | ||
|---|---|---|---|---|---|---|
| Density | ρ | g/cm³ | 3,2 | 5,9 – 6, 04 | >3,9 | 7.85 |
| Hardness | HV10 | N/mm² | 1700 – 2700 | 1300 – 1500 | 1800 | 700 |
| Young’s Modulus | E | GPa | 300 | 205 | 390 | 210 |
| Coefficient of Thermal Expansion | α | 10-6/K | 3.2 | 10.2 | 8,2 | 11.5 |
| Bending Strength | δB | N/mm² | 800 | 1000 – 1500 | 380 | > 2500 |
| Fracture Toughness | KIC | MPa m½ | 8 | 8 – 12 | 4,7 | > 20 |
| Thermal Conductivity | λ | W/m * K | 30 – 35 | 2 | 27 | 40 – 45 |
| Grain Size | d | µm | < 1 | < 1 | 1 – 5* | – |
Bearings are available in ISO-compliant measurements, in the precision classes P0, P6, P5 and P4; bearings can of course also be custom made to your individual specifications.