Views: 0 Author: Site Editor Publish Time: 2024-10-23 Origin: Site
In the industrial field, bearings are called the “joints” of industry and are essential components in many machines and equipment. Suitable bearings can help machines to support loads, reduce friction, and extend the service lifespan of moving parts.
According to the bearings’ raw materials, they usually can be divided into steel bearings (chrome steel, carbon steel, stainless steel, etc.) and ceramic bearings (zirconia, silicon nitride, etc.). It is noteworthy that, ceramic bearings, as an emerging bearing material, have received attention from many industries and fields.
In this article, LNB Bearing will introduce ceramic bearings in detail and explore the differences between them and steel bearings as well as their respective advantages and disadvantages. Hope to help customers better understand these two types of bearings and their characteristics so that they can make better choices.
Ceramic bearings are made of ceramic materials, as well as normal bearings, they are also mainly used to support rotating or moving shafts or parts. The most commonly used ceramic materials are silicon nitride (Si3N4), zirconium oxide (ZrO2), etc. Ceramic bearings are designed to reduce friction, improve wear resistance, and extend service lifespan.
The working principle of ceramic bearings is also similar to other types of bearings, reducing friction and wear through rolling elements between the inner and outer rings to achieve smooth movement. Due to their superior material properties, ceramic bearings are widely used in various types of machinery and equipment, especially in extremely harsh environments and special working conditions.
Ceramic bearings have a low density, so they are usually lighter than metal bearings, which helps to reduce the weight of the overall mechanical structure and improve the maneuverability of the equipment.
Ceramic bearings have a low friction coefficient, during the machinery operation, they can reduce heat generation, improve energy efficiency, and make their speed higher than steel bearings. So ceramic bearings are normally suitable for high-speed operation environments.
The ceramic materials' hardness is much higher than that of traditional metals. This property makes ceramic bearings effectively resistant to wear and scratches and suitable for heavy loads and high-frequency operation environments.
Ceramic materials have excellent corrosion resistance to many chemicals (such as acids and alkalis). Therefore, ceramic bearings are suitable for use in harsh environments, especially in the chemical and food industries.
Ceramic bearings can withstand higher temperatures than steel bearings and are suitable for high-temperature applications.
Ceramic bearings have low electrical conductivity. Since they cannot conduct electricity, they can prevent short circuits and arc discharges when used in electrical equipment, thereby eliminating the special need for bearing insulation in traction motors.
Ceramic bearings generate less noise during operation, so they are suitable for applications that require a quiet environment, such as precision instruments and high-end home appliances, etc.
Ceramics have a smaller thermal expansion coefficient, which can maintain better dimensional stability and will not deform significantly when the temperature changes.
According to different classification methods, ceramic bearings can be divided into many types. Herein, a simple classification will be made from three aspects: material, material composition, and structure.
The zirconium oxide material is used to make rings and rolling elements of the ceramic bearing, while generally, the cage uses PTFE and PVDF. There are also other cage materials like brass (Cu), nylon (RPA66-25), special engineering plastics (PEEK, PI), steel, stainless steel, etc. The zirconia bearings possess very good wear resistance and mechanical strength, which are suitable for use in highly corrosive environments such as chemical and medical equipment fields.
This kind of ceramic bearings' rings and rolling elements usually use the material of silicon nitride (Si3N4), the cage generally uses PTFE and PVDF. Compared with ZrO2 materials, the ceramic bearing of the Si3N4 material is adapted to higher speeds and load capacities and higher ambient temperature, and common applications in aerospace and high-speed machinery.
These types of bearings are made from alumina as the main material. They have good thermal conductivity and insulation properties, suitable for applications at high temperatures with high thermal management requirements.
The inner ring, outer ring, and rolling elements of this type of ceramic bearings are all made of ceramic materials, which have excellent corrosion resistance, wear resistance, high-temperature resistance, anti-magnetic and electrical insulation, etc. Full ceramic bearings are suitable for harsh and severe working conditions.
The inner ring or outer ring of hybrid ceramic bearings is usually made of metal materials (steel, stainless steel), while the rolling elements are made of ceramic materials (such as zirconium oxide, silicon nitride, etc.). This type of ceramic bearings combines the strength of metal with the low friction characteristics of ceramics. They are suitable for occasions requiring higher load capacity and wear resistance.
Full complement ceramic bearings are specially designed bearings in which the rolling elements (such as balls or rollers) almost fill the space between the inner ring and the outer ring. This design can increase the contact area, thereby improving the load capacity and rigidity.
Like ordinary bearings, ceramic bearings can be classified into many types according to their structure:
Ceramic deep groove ball bearings
Ceramic angular contact ball bearings
Ceramic self-aligning ball bearings
Ceramic thrust ball bearings
Ceramic cylindrical roller bearings
Ceramic tapered roller bearings, etc.
The Properties Comparison of Ceramic Bearings & Steel Bearings | ||
Item | Ceramic Bearing | Steel Bearing |
Materials | Zirconia (ZrO2), Silicon Nitride (Si3N4), Alumina (Al2O3), etc. Carbon steel, Chrome steel, Stainless steel, etc. | Carbon steel, Chrome steel, Stainless steel, etc. |
Density | Lower density | Higher density |
Friction | Low friction coefficient | High friction coefficient |
Operating Temperature | Good temperature resistance, up to about 800℃ | Poor temperature resistance, 100-200℃ |
Corrosion Resistance | Good; suitable for chemical and humid environments | Poor; stainless steel can be used in humid environments, but not in corrosive chemical environments |
Hardness | High | Low |
Thermal Conductivity | Low | High |
Electrical Conductivity | Low conductivity, electrical insulation | Yes |
Speed | Fast | Slow |
Magnetism | No | Yes |
Wear Resistance | Very good | Good |
| The Advantages Comparison of Ceramic Bearings & Steel Bearings | |
Ceramic Bearing | Steel Bearing |
1. High speed 2. Light weight 3. Strong corrosion resistance, acid and alkali resistance, rust resistance 9. Oil-free self-lubricating 10. Long service lifespan | 1. Low cost |
The Disadvantages Comparison of Ceramic Bearings & Steel Bearings | |
Ceramic Bearing | Steel Bearing |
1. High cost |
2. Large friction coefficient and high loss 4. More prone to fatigue failure under repeated loads |
Aircraft and spacecraft face very harsh operating environments. Due to ceramic bearings have many advantages such as being lightweight, having low friction coefficient, high-temperature resistance, corrosion resistance, and others, they can work in super extreme environments.
The medical equipment including surgical instruments, dental equipment high-precision medical equipment, etc. These medical machines normally demand very clean and sterile working environments. Ceramic bearings are organism-friendly and can reduce infection. They have antibacterial properties and provide the advantages of easy cleaning, corrosion resistance, and so on. For these reasons finding a great application in medical appliances and equipment, particularly in those areas where chemical cleaning agents or disinfectants are used.
Ceramic bearings boast advantages such as lightweight, good wear resistance, and low friction coefficient; they find wide applications in high-performance vehicles.
In the chemical and pharmaceutical industries, mechanical devices are often put into a terrible atmosphere of corrosive chemicals or high-temperature conditions. Ceramic bearings with features like corrosion resistance and high-temperature resistance can enhance the working effectiveness of machinery while prolonging the service life of mechanical devices.
Ceramic bearings boast electrical insulation and low thermal expansion. This makes them highly suitable for use in high-frequency, high-power, and high-precision electronic equipment to improve the overall performance, ensuring reliability in mechanical equipment.
Ceramic bearings have the qualities of resistance to high temperature and corrosion and are easy to clean; thus, they are usually used for food processing and beverage filling machines, contributing much to the hygiene and safety of the whole production process and reducing the risks of cross-contamination.
