Silicon Nitride Bearings
Silicon Nitride is a high-melting-point ceramic material that is extremely hard and relatively chemically inert. The material is prepared by heating powdered silicon between 1300 °C and 1400 °C in an atmosphere of nitrogen. Then the powder of silicon nitride can be sintered to designed shape. Silicon Nitride is an ideal material for bearings. Ceramic bearings have good wear and corrosion resistance, and great mechanical strength under high temperature. We can supply full ceramic and hybrid bearings made by Silicon Nitride, Zirconia as well as SiC.
Comparison of ceramic and steel for bearings
|Density||3.24 g/cm3||6 g/cm3||7.8 g/cm3|
|Thermal expansion coeff.||3.4×10-6||10.5||12.5×10-6|
|Hardness, HV||1500||1300||About 750|
|Young’s Module||320 GPa||210 GPa||208 GPa|
Silicon nitride ceramic is an ideal material for bearing parts. Si3N4 bearings have already been applied in automobiles, rockets high-speed engines, equipment working in a corrosive environment and some performance model cars. Compared with steel, high-performance ceramic balls have better mechanical properties under high temperature and could survive from most the corrosive chemicals. As the price of ceramic materials decreased, it could have more applications.