What are the advantages of ceramic bearings?

Ceramic bearings might be more expensive than steel, but these bearings provide reduced friction, reduced weight and have the potential to last much longer than the traditional stainless-steel offering in many harsh environments. That said, the application needs to warrant the increased price.

25MM UCFL305-16 Flange Unit Medium Duty BearingT

Full ceramic bearings are generally used in environments that are too hostile for steel bearings such as temperature extremes or use with corrosive chemicals or liquids. Consider bearings for marine applications as an example. Ceramic bearings can provide excellent resistance to salt water, prolonging the lifespan of the bearing in ocean environments. However, full ceramic options are not recommended where heavy shock loads are likely, due to the bearings risk of cracking. In these instances, 316 stainless steel bearings might be a better option as long as the load is low.

Can you lubricate ceramic bearings?

Full ceramic bearings do not need lubricant to operate as the coefficient of friction of our full ceramic bearings is very low. However, lubrication can be used to keep the ceramic material from wearing down prematurely and extend bearing life.

The differences between full ceramic and hybrid bearings?

Full ceramic bearings have excellent corrosion resistance and can cope with very extreme temperatures but due to the more brittle nature of ceramics, the maximum speed is 20% to 25% of the all steel equivalent due to the risk of sudden failure caused by cracking at higher speeds. The maximum load of a full ceramic bearing is around 65 to 75 percent of the load that a steel bearing can support.

Hybrid bearings use steel rings and ceramic (usually silicon nitride) balls. This combination means that hybrid bearings can run at higher speeds due to the more forgiving nature of steel and the lower centrifugal force generated by the lightweight ceramic balls but they are limited in terms of corrosion resistance and extreme temperature capability by the material of the rings.

Shock or sudden impact loads should be avoided with both full ceramic bearings and hybrid bearings. The steel rings in a hybrid bearing will withstand shock loads much better than ceramic rings but, in the event of a sudden impact load, the much harder ceramic balls will make indentations in the steel raceways leading to rapid wear and early failure.

Full ceramic bearings can run without lubrication. Because of the ceramic balls, hybrid bearings cope well with marginal lubrication but they should be adequately lubricated as the ceramic balls will abrade the steel rings much faster if run dry unless speeds are kept low.

Can full ceramic bearings rust?

Choosing a full ceramic bearing will save you the headache of dealing with rust. These bearings are designed to be corrosion resistance and to be used for long periods of time in highly corrosive environments. Where even stainless steel bearings would suffer with rusting, full ceramic bearings will not. However, ZrO2 bearings may degrade and weaken over a period of time while exposed to hotwater or steam. 

In the case of hybrid bearings - those with steel races but ceramic balls - the ceramic balls of these bearings will not rust but the rest of the bearing will need to be maintained against rust.

Before selecting either a hybrid or full ceramic bearings, we suggest asking a member of the SMB Bearings team to consult you on the best bearing for your application. You can contact the team here.

Can full ceramic bearings shatter?

Yes. Full ceramic bearings have load ratings 25 to 35 per cent lower than steel bearings. As the material is much harder, it is also more brittle. Therefore, when put under too much pressure, ceramic material may crack while steel is more likely to suffer indentations.

Before deciding to use full ceramic bearings, it is important to assess whether the bearing can handle the planned load. You should also consider the presence of any sudden, heavy impact loads which full ceramic bearings do not tolerate as well as steel bearings. For impact loads, a steel or stainless steel bearing would be a better option.

If you are unsure which bearing material is right for you, check out of these common bearing FAQs. Here, you will find bearing material comparisons, such as stainless steel bearings vs ceramic bearings. This should help you select the right material.

Can ceramic bearings run dry?

Full ceramic bearings do not require lubrication to run. Ceramic is non-porous and as a result, it is practically frictionless. Dry ceramic bearings are an option. Unlike stainless steel bearings, full ceramic bearings do not suffer heat build-up within the bearing and therefore do not need lubrication to help dissipate the heat although an effective lubricant can be used to support higher speeds.

Full ceramic bearings are the only type of bearing recommended to run dry at anything other than very low speeds. For other bearing materials, lubrication can be essential to the bearings operation. 

Find out more about our bearing relubrication service here.

How long do ceramic bearings last?

The lifespan of a bearing doesn’t necessarily relate to its material, but rather whether it is the correct type of bearing for the application. Cheap bearings won’t last as long compared to higher quality versions. More importantly, a bearing certainly won’t last long if it is not suitable for the application at hand. In aggressive environments, full ceramic bearings will last significantly longer than steel bearings but how long can depend on the chemicals in contact with the bearings, the temperature, the presence of contamination and the speed and load.

For a quick consultation on what bearing is right for you, contact the team today.

By keeping our product range specialised and clearly defined, we know our products well allowing us to give you a better service with excellent technical back-up. SMB Bearings originally specialised in miniature bearings, thin-section bearings and stainless steel bearings. By natural progression, we expanded the range to include other corrosion resistant bearings such as plastic bearings, 316 stainless bearings and ceramic bearings.