Advantages and disadvantages of ceramic bearing

Ceramic materials are found in all kinds of art and utensils. We all know tiles, pans, brake discs and dental fillings. The word ceramic is derived from the Greek word kéramos, meaning "clay" or "baking pot". This suggests the origins of ceramics; a manufacturing process that involves heating.

Ceramics have many properties that make them ideal for use in bearings. Most ceramics are hard, wear-resistant and non-conductive. The first ceramic bearings were designed in the United States as early as the 1960s and 1970s. Today, they are used in aerospace, medical and automotive industries, among other applications. New developments in electric vehicles mean they are becoming increasingly popular.

Ceramic bearings are lighter and more durable than ordinary steel bearings. There are several types. Hybrid bearings (such as the Schaeffler HC version) contain ceramic and steel components. The rolling elements are ceramic balls or rollers, while the inner and outer rings are made of steel. There are also full ceramic bearings, which do not have any steel components. These are usually made of silicon nitride (Si3N4) or zirconium oxide (ZrO2). Hybrid and full ceramic bearings have some advantages. They are:

• Electrically insulating
• Suitable for high speeds
• Highly resistant to wear and abrasion
   

Ceramic materials do not conduct electricity. This is an indispensable quality for bearings in generators, traction motors and other electric motors. As we pointed out in our blog on premature bearing failure, electrical currents can cause serious damage to ordinary bearings. This does not happen with hybrid bearings. The electrically insulating ceramic balls protect the steel rings from the penetration of electrical current. In addition, all-ceramic bearings are non-magnetic. For this reason, they are often used in medical devices.

Furthermore, ceramic bearings and hybrid bearings with stainless steel rings (such as the Schaeffler XC model) are more corrosion-resistant than steel bearings. For example, they are resistant to water, detergents and certain chemicals. They can also withstand high temperatures. They can achieve higher rotational speeds than steel bearings of the same size. Hybrid bearings can withstand higher speeds than all-ceramic bearings. In fact, their steel rings are less brittle than ceramic bearings. This makes them less susceptible to sudden failure under overload or speed.

Ceramic balls have a lower density than steel balls but are significantly harder. They are very wear-resistant: small particles that enter the bearing are crushed. And their very low rolling resistance ensures that almost no heat is released. This way, the service life of the lubricant is longer. Hybrid bearings are also more resistant to adverse lubrication conditions than steel bearings. Full ceramic bearings can even be used without lubricants.

Ultra-wear-resistant and able to withstand extreme conditions…Use ceramic bearings all the time from now on? It depends on their use. Ceramic and hybrid bearings have a lower load-carrying capacity than steel bearings. Since the ceramic roller body is harder, it deforms less. The result is a smaller contact ellipse. In addition, steel bearings are better resistant to thermal shock. But most importantly, ceramic bearings are expensive. This is because the raw materials of these bearings are complex and energy-intensive to process. Therefore, production takes a long time. So before making a choice, determine which features are important for your application!

Looking for ceramic bearings or other models for special applications? Contact ：alita@sgsabearing.com . We will be happy to help you.