Silicon nitride ceramic bearing retain some excellent performance such as high temperature resistance, high corrosion resistance, high abrasion resistance, electrical resistivity,self-lubrication, Compared with ZrO2, full ceramic bearings made of Si3N4 are suitable to endure heavier load and higher temperature environment, which help to extend the application, such as high-speed bearings, high temperature bearings, corrosion-resistant bearings, shielded bearings, electrical insulation bearings and so on.