Ceramic Bearings

Performance comparison of four bearing materials: ordinary bearing steel AISI52100 (GCr15), stainless steel AISI440 (9Cr18), silicon nitride (Si3N4) and zirconium oxide (ZrO2). As an important mechanical foundation, ceramic bearings are leading the world of new materials due to their excellent performance that metal bearings cannot match, such as high temperature resistance and super strength. In the past decade, they have been increasingly widely used in various fields of national economy and people's livelihood.

Product Advantages

1. Since ceramics are almost not afraid of corrosion, ceramic rolling bearings are suitable for working in harsh conditions full of corrosive media.

2. Since the density of ceramic rolling balls is lower than that of steel and the weight is much lighter, the centrifugal effect on the outer ring during rotation can be reduced by 40%, thereby greatly extending the service life.

3. Ceramics are less affected by thermal expansion and contraction than steel, so when the bearing clearance is constant, the bearing can be allowed to work in an environment with more drastic temperature changes.

4. Since the elastic modulus of ceramics is higher than that of steel, it is not easy to deform when subjected to force, which is conducive to increasing the working speed and achieving higher precision.

Product Usage

Ceramic bearings have the characteristics of high temperature resistance, cold resistance, wear resistance, corrosion resistance, anti-magnetic and electrical insulation, oil-free self-lubrication, and high speed. They can be used in extremely harsh environments and special working conditions, and can be widely used in aviation, aerospace, navigation, petroleum, chemical industry, automobiles, electronic equipment, metallurgy, electricity, textiles, pumps, medical equipment, scientific research, and national defense and military fields. They are high-tech products for the application of new materials.

The rings and rolling elements of ceramic bearings are made of all-ceramic materials, including zirconium oxide (ZrO2), silicon nitride (Si3N4), and silicon carbide (Sic). The retainer is made of polytetrafluoroethylene, nylon 66, polyetherimide, zirconium oxide, silicon nitride, stainless steel or special aviation aluminum, thereby expanding the application of ceramic bearings.

Application Areas

Medical equipment, cryogenic engineering, optical instruments, high-speed machine tools, high-speed motors, printing machinery, food processing machinery.

In the fields of aerospace, navigation, nuclear industry, petroleum, chemical industry, textile industry, machinery, metallurgy, electricity, food, locomotive, subway, high-speed machine tools, scientific research, national defense and military technology, etc., it is necessary to work under special working conditions such as high temperature, high speed, deep cold, flammable, explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction, etc., and the indispensable replacement role of ceramic bearings is gradually being recognized by people.

With the continuous advancement of processing technology and the increasing improvement of process level, the cost of ceramic bearings has been continuously reduced. It has been gradually extended from being used in a small range in some high, precise and advanced fields in the past to various industrial fields of the national economy. The market price of products is gradually approaching practicality and reaching a level acceptable to users. The wave of large-scale application of ceramic bearings has come!

Usage Classification

(1) High-speed bearings: They have the advantages of cold resistance, low elasticity, high pressure resistance, poor thermal conductivity, light weight, and low friction coefficient. They can be used in high-speed spindles of 12,000 rpm to 75,000 rpm and other high-precision equipment;

(2) High-temperature resistant bearings: The material itself has a high temperature resistance of 1,200°C and good self-lubrication. The operating temperature is between 100°C and 800°C without expansion caused by temperature difference. They can be used in high-temperature equipment such as furnaces, plastics, and steelmaking;

(3) Corrosion-resistant bearings: The material itself has corrosion resistance and can be used in strong acid, strong alkali, inorganic, organic salt, seawater and other fields, such as electroplating equipment, electronic equipment, chemical machinery, shipbuilding, medical equipment, etc.

(4) Anti-magnetic bearings: Because they are non-magnetic, they do not absorb dust, which can reduce the peeling of the bearing surface and thus reduce the running noise. They can be used in demagnetization equipment and precision instruments.

(5) Electrically insulated bearings: Due to their high resistivity, they can prevent arc damage to bearings and can be used in various electrical equipment that require insulation.

(6) Vacuum bearings: Due to the unique oil-free self-lubricating properties of ceramic materials, they can overcome the problem of ordinary bearings being unable to achieve lubrication in ultra-high vacuum environments. Note: For the above five types of bearings, the same set of bearings can be applied to high temperature, high speed, acid and alkali, magnetic field, and non-insulation, but because the material properties are different (please refer to the rare earth ceramic material performance table), please choose the ceramic bearings with the most suitable materials according to the occasions you are applying when choosing products.

Material Classification

Zirconia

Full ceramic bearings have the characteristics of anti-magnetic and electrical insulation, wear resistance, corrosion resistance, oil-free self-lubrication, high temperature resistance and high cold resistance, and can be used in extremely harsh environments and special working conditions. The rings and rolling elements are made of zirconium oxide (ZrO2) ceramic material, and the retainer uses polytetrafluoroethylene (PTFE) as standard configuration. Generally, glass fiber reinforced nylon 66 (RPA66-25), special engineering plastics (PEEK, PI), stainless steel (AISISUS316), brass (Cu), etc. can also be used.

Silicon nitride

Silicon nitride full ceramic bearing rings and rolling elements are made of silicon nitride (Si3N4) ceramic material. Generally, RPA66-25, PEEK, PI, and phenolic cloth-reinforced bakelite tubes can also be used. Compared with ZrO2 materials, SiN4 full ceramic bearings can be used for higher speeds and load capacities, as well as higher ambient temperatures. At the same time, precision ceramic bearings for high-speed, high-precision, and high-rigidity spindles can be provided, with the highest manufacturing accuracy reaching P4 to UP level.

Full-fill ball bearings

Full-fill ball bearings have a gap for adding balls on one side. Because they adopt a cage-free structure design, they can fit more ceramic balls than standard bearings, thereby improving their load capacity. In addition, they can avoid the limitation of cage materials and achieve the corrosion and temperature resistance of ceramic cage-type full-ceramic bearings. This series of bearings is not suitable for high speeds. When installing, pay attention to installing the gap surface on the end that does not bear axial load.

Hybrid

Ceramic balls, especially silicon nitride balls, have the characteristics of low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity. They are particularly suitable for high-speed, high-precision and long-life hybrid ceramic ball bearings (inner and outer rings are metal). Generally, the inner and outer rings are made of bearing steel (GCr15) or stainless steel (AISI440C), and ceramic balls can be made of ZrO2, Si3N4, or SiC.