|Hybrid ceramic bearing- steel/stainless steel rings & ceramic balls)|
Our famous skate bearings - CB608TW-2RU P5 - chrome rings & ceramic balls, rubber seals, dimensions 8x16x5mm - buy these direct from our EBAY SKATE SHOP.
SCB6002 - stainless steel rings & ceramic balls, dimensions 15x32x.9mm
SCB626 - stainless steel rings & ceramic balls, dimensions 6x19x6mm
SCB6801 - stainless steel rings & ceramic balls, dimensions 12x21x5mm
SCB6807 - stainless steel rings & ceramic balls, dimensions 35x47x7mm
SCB6810 - stainless steel rings & ceramic balls, dimensions 50x65x7mm
SCB6902 - stainless steel rings & ceramic balls, dimensions 15x28x7mm
SCBR144TWZW09 - stainless steel rings & ceramic balls, one metal shield, dimensions 0.1250x0.2500x0.1094"
We can order other sizes in from the factory for you, so please contact us if you need any further information or advice.
• Good corrosion resistance to cold water and many chemicals
Silicon Nitride (suffix "Si3N4")
Bearings can be supplied with steel rings and ceramic balls (hybrid) or "all ceramic" bearings with ceramic rings and balls. These all-ceramic bearings may have PTFE or PEEK retainers or be supplied as full complement type.
Hybrid bearings (CB/SCB prefix) have steel rings and ceramic balls. Silicon nitride is the most popular for the balls as it has only 40 percent of the density of bearing steel but is much harder giving greater wear resistance. Zirconia is heavier with 75 percent of the density of steel so is less suitable for hybrid bearings.. Hybrid bearings are also capable of higher speeds. Sometimes, excessive claims are made about the high speed capabilities of hybrid bearings. They can run faster than all steel bearings due to the lower centrifugal force generated by the ceramic balls but this is partially counteracted by the lower elasticity of the balls. As the balls are harder, the contact area between the balls and the raceway is smaller which causes a higher contact pressure which can can cause the raceways to wear faster. The speed increase for hybrid bearings is approximately 30-40 percent with adequate lubrication. Hybrid bearings can also operate better with limited lubrication but running speed should be reduced. Hybrid bearings are also less subject to ball skidding under inital acceleration.
All-ceramic bearings (CC prefix) have good to excellent corrosion resistance, are non-magnetic and, apart from silicon carbide, are electrically insulating. All-ceramic bearings can be used in high to very high temperatures if supplied without a cage (full complement).
- Electrical resistance: Si3N4 best, then ZrO2, then SIC which is conductive.
- High temp resistance: SiC best (1600C), then Si3N4 (1000C), then ZrO2 (300C)
- Corrosion resistance: SIC (excellent), then Si3N4 (very good) and ZrO2 (good)
- Load capacity: SIC highest then Si3N4, then ZrO2
- Fracture toughness: ZrO2 best, then Si3N4, then SiC
WARNING: Hybrid bearings can offer very low frictional torque but the bearing rings must have very good roundness and a high quality raceway finish while the balls must also have very good roundness and surface finish. A lower quality hybrid bearing can have much higher friction levels and a lower maximum speed than a good quality all-steel bearing...
Any questions? Please feel free to contact us for further assistance!