Ceramic bearings tend to overshadow their steel counterparts. In many non-magnetic and non-conductive medical or semiconductor devices, ceramic bearings should be the first choice. Extensive knowledge of the AUB Bearings technical team. For many years, AUB has been a high-quality bearing manufacturer and supplier, focusing on different series of bearings, including full ceramic bearings and hybrid ceramic bearings.
The races and balls of all-ceramic bearings are entirely made of ceramic materials, which are superior to ordinary steel bearings in many ways. Ceramics are an ideal material for any application looking to achieve higher speeds, reduce overall weight, or in extremely harsh environments where high temperatures and corrosive substances are present. the
Ceramic hybrid bearings are the most common type of ceramic bearing and consist of a steel inner and outer ring with ceramic (usually Si3N4) balls instead of steel. Common ceramic bearing types are angular contact and deep groove ball bearings. Ceramic hybrid bearings are the most common type of ceramic bearing and consist of steel inner and outer rings with ceramic (usually Si3N4) balls instead of steel.
Ceramic bearings are usually made of the following materials:
Since ceramic is a glass-like surface, it has an extremely low coefficient of friction, making it ideal for applications seeking to reduce friction. Ceramic balls require less lubrication and are harder than steel balls, which will help extend bearing life. Thermal performance is better than steel balls, so less heat is generated at high speeds.
The cages of all-ceramic bearings are usually made of high-performance plastics, such as PEEK or PTFE. AUB's ceramic bearing cages are made of polyether ether ketone (PEEK), a thermoplastic used in various semiconductor applications . PEEK is lightweight, has very good mechanical properties, high operating temperature and good resistance to media. For extreme temperatures (to -253°C), polychlorotrifluoroethylene (PCTFE) is used instead of PEEK, which also provides better media resistance. When the temperature exceeds 250°C, heat-resistant steel is used as the cage material.
Ceramic balls are rounder, lighter, harder and smoother than steel balls due to their lack of porosity. This reduces friction and energy loss, allowing your equipment to run more efficiently (and for longer) with ceramic ball bearings. Because they are relatively smooth, ceramic ball bearings require less lubrication than steel bearings.
• Ceramic bearings can run without lubrication. This is because ceramic materials do not microweld. Micro-welding occurs when surface imperfections on the rolling elements and raceway interact to cause arcing, usually in the metal. This can degrade the surface and significantly reduce bearing life. Ceramic materials do not have this problem, making them suitable for a variety of applications requiring a lubrication-free environment.
• They usually have very high hardness (70-90 HRc) and modulus of elasticity or Young's modulus. This means they resist shape change when a load is applied, while improving wear characteristics.
• Corrosion. Ceramics are non-metallic and non-ferrous materials. They will not corrode like metal when exposed to water and other hazardous chemicals. Their high corrosion resistance allows them to perform well in wet and chemically aggressive environments.
• Bearing race.Ceramic balls are much less elastic than steel balls, and this is something to keep in mind when considering an upgrade to ceramic bearings. Ceramic balls are more likely to cause damage (indentation) to the bearing raceways if you experience heavy spindle loads or a spindle crash. Over time, the dimples in the raceways can grow larger and eventually lead to spindle failure.
Conductivity.Due to the lack of free electrons in most ceramics, ceramic bearings are non-magnetic and non-conductive, so they are often preferred in applications where conductivity is a concern – for example, if you have a motor controlled by a variable frequency drive.
• Accuracy.In terms of accuracy, there is very little difference between ceramic bearings and steel bearings. The only difference is that ceramic bearings don't thermally expand like steel bearings, so don't generate as much heat at high speeds, and don't experience as much measurable thermal growth.
• Expensive. Ceramic bearings are on average 50% more expensive than steel bearings. The first thing people may notice when researching ceramic bearings is that they are much more expensive than metal bearings. This thing is caused by many reasons. The large amount of energy required to reach the temperatures required for the sintering process of advanced raw materials is associated with extremely high energy and processing costs. Because ceramics are so hard, machining and grinding costs add up quickly when manufacturing precision bearings. All of this must be done in a clean environment by a skilled workforce. Ceramics are extremely sensitive to impurities in their pores, so any contamination can cause premature failure. As the size increases, the price increases exponentially due to the need for costly processing methods. These include the slower sintering process required to overcome temperature gradients in the green body, the amount of pressure applied uniformly over a larger volume, and the resulting machine costs.
• Low bearing capacity. Compared to metals, ceramic bearings have a lower load-carrying capacity and are sensitive to thermal shock. Thermal shock is when a temperature gradient inside a material causes differential expansion and thus internal stress. This stress can exceed the strength of the material, causing cracks to form.
• Ceramics are also more difficult to obtain a high-quality surface finish. They can be ground to a surface finish of Ra 0.1, thus achieving a P5 precision class.
Space exploration applications and other aerospace industry products often rely on ceramic bearings. Lightweight and vacuum-compatible bearings make them ideal for satellites and spacecraft that require optimal weight-bearing capabilities for enhanced flight dynamics and acceleration. Additionally, these bearings can operate without lubricants, such as heavy greases and oils, that tend to attract contaminants that interfere with sensitive electrical components. There are many common applications that are closely related to our daily life. The service life of most railway traction motors is improved by ceramic materials. Chemical and hybrid applications also benefit from the use of ceramic bearings, especially for protection against contamination. Because ceramic bearings are chemically inert, they will not react with harsh chemicals or leach particles into sensitive solutions. The corrosion-resistant properties of ceramic bearings make them ideal for cleaning with strong acid or alkaline chemical cleaning solutions. Additionally, the absence of oil- and grease-based lubrication reduces the chances of bacterial growth and contamination. Some other applications of ceramic bearings include:
Ceramic bearings have a wide range of advantages in engineering applications, but there are also disadvantages that must be considered. They are very hard, corrosion resistant and have a high modulus of elasticity. They are able to run without lubrication, have low thermal expansion, are usually low density and are non-magnetic. However, they are expensive, have low load-carrying capacity, are sensitive to thermal shock, and are difficult to achieve a high-quality surface finish. Whether you use silicon nitride, zirconia or silicon carbide, ceramic bearings are used in a wide range of applications including aerospace, chemical, medical and scientific instruments.