... coefficient Ceramic hybrid bearing 608LLU Ceramic ball especially Si3N4 have the following performance as low density, high strength, low friction ... working, it's the best choice for rollers (inner ring and outer ring are made by metal) of the hybrid construction which has ... . Normally, GCr15 or (AISI440C,316 304) makes inner ring and outer ring; The ceramic ball can adopt ZrO2, Si3N4 or Sic. ZrO2 ...