Silicon Nitride(Si3N4) full ceramic ball bearing 1.special electrical, magnetism,wear,corrosion resitance 2.maintenance free Silicon Nitride(Si3N4) full ceramic ball bearing1.Full ceramic bearing made with ZrO2 ... environment and specially condition,2.The rings and balls: full ceramic materia:ZrO23.The cage :PTFE, GFRPA66-25,PEEK,Phonemic Textiles Tube,etc. full ceramic bearing of silicon nitride ...