Feasibility Analysis of Ceramic Bearings in Chinese Market

In the early 1960s, researchers found that engineering ceramics have excellent properties as bearing materials, such as high-temperature resistance, corrosion resistance, wear resistance, high hardness, low density, low coefficient of thermal expansion, and good self-lubrication, etc. However, the large elastic modulus of ceramic materials will increase the contact stress of bearing rolling elements on the inner and outer rings, and reduce the service life of bearings. Researchers have conducted a large number of experimental studies on various properties of ceramic materials, and believe that hot-pressed silicon nitride is the most suitable bearing material among all-ceramic materials.

In the 1970s, material experts focused their attention on exploring new bearing materials from all-ceramic materials to silicon nitride ceramic materials. Scot T, DALAL, and others believe that silicon nitride is a kind of material that can be wetted and can make lubricating oil form an oil film of appropriate thickness in the bearing. Hot pressed silicon nitride ceramics are the most wear-resistant material when not lubricated. The use of solid lubricants at high temperatures can eliminate the wear of hot-pressed silicon nitride materials. Under heavy-duty lubrication conditions, hot-pressed silicon nitride as a bearing material is not better than bearing steel. Under the same stress conditions, the service life L10 of silicon nitride hybrid bearing is many times longer than that of other ceramic hybrid bearings.

The fatigue failure mode of silicon nitride ceramic ball is similar to that of bearing steel, which is fatigue spalling rather than fracture. In terms of hybrid bearing performance, Parker et al. Believe that due to the high elastic modulus and low density of silicon nitride, the inner ring and outer ring of hybrid bearing are affected respectively, so the decrease in the service life of the inner ring of the hybrid bearing is greater than the increase in the service life of its outer ring, and ultimately the total service life of the hybrid ceramic bearing is reduced; The service life of the hybrid bearing is better than that of steel bearing under light load and high speed; For the silicon nitride rolling element, the quality of the surface processing of the rolling element has a great impact on its fatigue life, corrosion resistance and wear resistance. At the same time, the life of the hybrid ceramic bearing is also limited by the life of the steel race.