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Engineers, hobbyists, and equipment builders who demand reliable rotation in demanding environments know that standard steel bearings fall short when exposed to moisture, chemicals, or extreme speeds. Silicon nitride ceramic deep groove ball bearings are engineered for those exact conditions — delivering consistent, low-friction performance where metal bearings corrode, seize, or wear prematurely.
Each bearing is constructed from silicon nitride (Si₃N₄) ceramic balls paired with a steel outer and inner ring, held in place by a precision retainer. Available in inner diameters (ID) ranging from 3 mm (approx. 0.12 in) to 35 mm (approx. 1.38 in), with outer diameters (OD) from 7 mm to 62 mm and widths from 2 mm to 16 mm — covering standard series including 683, 684, 685, 686, 687, 688, 689, 693–699, 603–609, 6000–6007, 6200–6206, 6800–6808, and 6900–6906.
These silicon nitride ceramic ball bearings are widely used in RC car wheel hubs and drone motor shafts where weight savings matter, in laboratory centrifuges and medical devices requiring non-magnetic and non-conductive rotation, and in marine or chemical-processing equipment where corrosion resistance is non-negotiable. Their low density also makes them a go-to choice for high-speed spindle applications in CNC machining and precision tooling.
| Ball Material | Silicon Nitride (Si₃N₄) Ceramic |
|---|---|
| Ring Material | Chrome Steel (GCr15) — See variant options for stainless variants |
| Retainer Material | See variant options |
| Inner Diameter (ID) Range | 3 mm – 35 mm (approx. 0.12 in – 1.38 in) |
| Outer Diameter (OD) Range | 7 mm – 62 mm (approx. 0.28 in – 2.44 in) |
| Width Range | 2 mm – 16 mm (approx. 0.08 in – 0.63 in) |
| Bearing Series Covered | 683–689, 693–699, 603–609, 6000–6007, 6200–6206, 6800–6808, 6900–6906 |
| Bearing Type | Deep Groove Ball Bearing (Open / With Retainer) |
| Max Operating Temperature | Typically –40 °C to +120 °C (–40 °F to +248 °F) |
| Lubrication | See variant options |
| Sealing | Open (with retainer) |
| Radial Load Capacity | See variant options |
| Dynamic Load Rating | See variant options |
Select your bearing by matching three dimensions: Inner Diameter (ID) × Outer Diameter (OD) × Width (all in mm). These correspond to your shaft diameter, housing bore, and available axial space. The variant name in this listing follows the format [Series] ID*OD*Width mm — for example, [688] 8*16*5mm means ID=8mm, OD=16mm, Width=5mm.
Silicon nitride ceramic is harder than steel (Rockwell hardness ~78 HRC vs. ~60–65 HRC for bearing steel), which means the balls resist deformation and wear under load. However, ceramic is more brittle than steel under impact loads. These bearings excel in high-speed, light-to-moderate radial load applications rather than heavy shock-load environments.
Yes. Silicon nitride ceramic balls are chemically inert and will not rust or corrode when exposed to water, saltwater, or most common chemicals. The steel rings may require additional protection (such as stainless steel rings) in fully submerged or highly corrosive environments — check the specific variant or contact us to confirm ring material.
These bearings follow standard metric deep groove ball bearing dimensions (ISO 15:2017 series), so they are dimensionally interchangeable with standard steel bearings of the same series number. As long as your housing and shaft match the ID × OD × Width of the selected variant, they will fit without modification.
Absolutely. The lower density of Si₃N₄ balls reduces centrifugal force at high RPM, allowing higher limiting speeds compared to all-steel bearings of the same size. This makes them well-suited for drone motors, RC car wheel hubs, electric motor shafts, and CNC spindle heads where speed and low heat generation are priorities.
These bearings are supplied open (with retainer, no seals). We recommend applying a thin film of appropriate grease or oil before installation. For high-speed applications, a light spindle oil is preferred; for general use, a lithium-based grease works well. Avoid over-lubrication, which can increase drag and heat.
The series number indicates the bearing's dimensional family. The 600-series (683–689) are miniature bearings with very small IDs (3–9mm). The 6000-series are light-section bearings with moderate OD-to-ID ratios. The 6200-series have a heavier cross-section for higher load capacity. The 6800-series are thin-section bearings with a large OD relative to ID. The 6900-series fall between 6800 and 6000 in cross-section. Choose based on your load, speed, and space requirements.
