Surface Endurance and Lubrication of Silicon Nitride Ball Bearings.

Abstract : A report is made on the effect of using silicon nitride balls on the rolling contact fatigue life of radially loaded M50 steel ball bearings. Scanning electron microscope (SEM) examination of the surface topography of as-manufactured silicon nitride ball surfaces is described and compared with silicon nitride ball and flat washer surfaces tested previously. The rolling-contact fatigue performance of previously tested all-tool-steel bearings is compared with the present group of bearings containing silicon nitride balls as well as with previously tested silicon nitride flat washers run against tool steel rollers. It is shown that the life of the present group of bearings is controlled by the life of the currently available silicon nitride ball complement. This is contrary to the previous flat washer life results. The ball groove surfaces of the present steel bearing rings after running against the silicon nitride balls is described.