Comparing to metal materials, silicon nitride is a ideal materialfor structural applications for its excellent performance, such as high strength, hardness, wear-resistant, high rigidity, corrosion resistance, high temperature, electrical insulator, nonmagnetic, and low density etc. They are suitable for structural materials at elevated temperature, which have been the primarily choice material for ceramic bearings.
Their characteristics are shown as follows
1.High corrosion resistance, which means they can be also used in strong acid, strong alkali and seawater.
2.High temperature resistance.Si3N4 ceramic balls remain the same strength and hardness even in 1100.
3.Electrical insulation, non-magnetic, they can also be used in magnetic field.
4.Si3N4 ceramic balls have a low density of 3.26g/cm3. It is approximately 60% lighter than steel balls, which extremely decrease the centrifugal force on the groove, in order to effectively reduce the wear and tear.
5.High rigidity and strength. Compared with chronme steel, Si3N4 ceramic is twice higher in hardness and half higher in elastic modulus value.
6.The coefficient f thermal expansion ofSi3N4 is 3.2×10-6/K. It is nearly 25% of the chrome steel, which leads to a good thermal shock resistance.
7.The self-lubrication of Si3N4 ceramic ball bearings can help to solve the contamination and inconvenient caused by lubricator, it can also be used in vacuum and high temperature.
8.Low thermal conductivity.
Application fields: high precise ceramic bearings, high temperature bearings, vacuum bearings, nonmagnetic bearings, chemical pump, high temperature pump, ceramic valve ball, measure ball.
Silicon nitride ball types:
1.Silicon nitride balls with GPS preparation.
2.Silicon nitride balls with HIP preparation.
3.Silicon nitride balls with Japan Toshiba ball billet.
Recently, silicon nitride bearing balls(Ø50-Ø101.6mm diameter) were prepared with high density of 3.3g/cm3, extraordinary mechanical properties.