Ceramic ball especially Si3N4 have the following performance as low density, high strength, low friction coefficient, electrical and magnetism resistance, wear resistance, well rigidity, self-lubrication it's the best choice for rollers (inner ring and outer ring are made by metal) of the hybrid construction ceramic ball bearings with long life which are used in high-speed, high accuracy environments. Normally, GCr15 or (AISI440C, 316 304) makes inner ring and outer ring, sometimes, there are ceramic inner ring and ball, and metallic outer ring. The ceramic ball can adopt ZrO2, Si3N4 or Sic.