Sets of circle and roll body of Silicon Nitride all-ceramic bearing adopt silicon nitride ceramic material,the keeper usesd the politef (PTEE) as the standard configuration, it can also generally used GRPA66-25,PEEK, PI and phenol aldehyde insert bakelite of cloth in charge of etc.. SI3N4 can be suitable for higher rotational speed and load ability to compare with ZrO2 material while making the ceramic bearing of right, and is suitable for higher ambient temperature. Can offer the quiet ceramic bearing used in the high-accuracy main shaft of high rigidity of high speed at the same time, make precision and reach P4 to UP grade at most.