Failure of Silicon Nitride Rolling Elements with Ring Crack Defects
This source preferred by Mark Hadfield
Authors: Hadfield, M.
Journal: Ceramics International
Hot isostatically pressed silicon nitride rolling elements are currently used in hybrid rolling element bearings. Surface defects such as ring cracks are difficult to detect during high volume production processes and hence there is a need to assess their influence on the rolling contact performance of the material. An accelerated rolling contact fatigue bench test is used to examine failure mode and performance of silicon nitride rolling elements with and without surface ring cracks. The surface ring cracks are found on silicon nitride as purchased from manufactures and are not produced artificially. Experimental test results are presented with pre-test surface analysis using a dye penetration technique. Theoretical calculations of the lubrication regime, contact stress fields and finite element analysis are presented. Scanning electron microscopy is employed to observe the failure modes of the silicon nitride rolling elements.