What are the advantages of ceramic bearings and hybrid ceramic bearings?

Ceramic materials have good corrosion resistance and high temperature resistance. We all know that ceramics are inert materials, while metals are active materials. Therefore, compared with metals, ceramics can resist corrosion from a variety of chemicals (including acids and alkalis). Because of this characteristic, ceramic materials are used in many industries, including bearings.

Among bearings, the ceramic bearings that people often call are actually hybrid ceramic bearings. This kind of bearing uses ceramic rolling elements and metal inner and outer rings. In addition to hybrid ceramic bearings, there are also all-ceramic bearings. What is the difference between these two bearings? ?

As the name implies, all ceramic bearings are made of ceramics, including bearing rings and balls. Of course, the cage is generally not made of ceramic, but is made of PEEK or PTFE resin. They have strong acid and alkali resistance, so they are suitable for Used in highly corrosive environments. Silicon nitride (Si3N4) bearings can withstand temperatures up to 800 degrees Celsius when used without a cage. Ceramic bearings weigh only 45% of the weight of metal bearings of the same size, so they rotate faster and are quieter.

In addition to the above properties, all-ceramic bearings are non-magnetic and therefore can be used in medical equipment such as MRI scanners, or any application with strong magnetic fields. However, the greater hardness of ceramic bearings also means greater brittleness, and therefore, ceramic bearings cannot withstand impact loads well.

Hybrid ceramic bearings are located between full ceramic bearings and steel bearings. Hybrid ceramic bearings use ceramic balls paired with metal inner and outer rings. The bearings with this combination (metal ferrule + ceramic balls) rotate at a higher speed than full ceramic bearings. .

Although the design differences are small, hybrid ceramic bearings are very different from all-ceramic bearings. For example, all-ceramic bearings do not require lubrication, but hybrid ceramic bearings do. Although the ceramic balls will still wear the steel ferrules, due to the friction of the balls Low coefficient and lightweight, hybrid ceramic bearings can handle edge lubrication better than steel bearings.

When using hybrid ceramic bearings at very low speeds, lubrication may not be required, however, as these bearings are typically selected for higher speed applications than full ceramic bearings, proper lubrication is recommended with a high speed cage The precision hybrid ceramic bearings enable very high speeds and are therefore used in applications such as machine tool spindles.

The corrosion resistance of the bearing will also be affected when hybrid rather than all-ceramic bearings are selected. Although ceramic balls have high corrosion resistance, due to the use of metal ferrules, even stainless steel has far less corrosion resistance. Much lower than ceramic, so overall corrosion resistance is also reduced.