Ceramic Roller Bearings for High Speed and High Temperature Applications

Hot pressed silicon nitride has excellent rolling contact fatigue resistance, good wear characteristics, and excellent dimensional stability in addition to its known physical properties of a low density and excellent elevated temperature strength and hardness. Precision quality roller bearings have been fabricated with silicon nitride rolling elements and M-50 steel races and, also, with both races and the rollers made from silicon nitride. These bearings, tested at speeds to one-half million DN (bore diameter × speed in rpm) and under heavy loads to give accelerated test conditions, show promise for the use of hot pressed silicon nitride as a bearing material.