All ceramic bearings are very expensive! Therefore, cheaper steel bearings will be used in traditional applications. But in practical applications, ceramic bearings have to be used in some special fields. What are the reasons for them?
The manufacturing materials of all-ceramic bearings usually include silicon nitride (Si3N4), zirconia (ZrO2), aluminum oxide (Al2O3) or silicon carbide (SiC), among which the all-ceramic bearings made of zirconia (ZrO2) and silicon nitride (Si3N4) are the most common.
Features of all-ceramic bearing:
The seat ring and ball are completely made of ceramic materials, and their hardness, corrosion resistance and other properties are much higher than those of ordinary steel bearings.
Achieve higher rotational speed, reduce total weight, and also adapt to extremely harsh environments such as high temperature and corrosion.
The preparation cost of all-ceramic bearings is high. At present, they are mainly used in the following special industries:
Cryogenic pump technology
Ceramic bearings can well adapt to high and low temperature applications. Especially in the field of low temperature, the application ambient temperature is far below zero. Extremely low operating temperature will have a direct impact on the viscosity of lubricant, resulting in insufficient lubrication and component burns. Ceramic bearings can also be used in cryogenic pumps without lubricant to avoid abnormal bearing operation caused by lubricant viscosity changes. Cryogenic ceramic bearings can be used for various liquid pumps such as liquefied natural gas pumps, liquid nitrogen (hydrogen, oxygen) pumps, butane pumps, liquid pumps for rocket missiles, spacecraft, etc;
mri scanner
Magnetic resonance imaging technology usually works with the MRI scanner of the hospital, and can generate two-dimensional and three-dimensional images of any living object. However, the equipment and components of these scanners are required to be nonmagnetic. Steel bearings are obviously inappropriate. The ceramic bearings are made of nonmagnetic materials and can operate stably at high speed with low noise. Therefore, they are very suitable for the application of nuclear magnetic resonance scanners.
Clean room equipment
The clean room is required to be nearly dust-free, so as to realize the preparation and measurement of small and high-precision instruments and equipment or materials in a pollution-free environment. The lubricant of the standard steel bearing may be dispersed to the external environment, resulting in the weakening of the control ability of the clean room's dust-free conditions. The all-ceramic bearing can avoid this situation. The surface of ceramic bearing is also very smooth, which can realize the work without lubricant. Compared with the stainless steel bearing, the all-ceramic bearing is not easy to accumulate heat inside and does not need lubrication and heat dissipation.