Detection of Surface Defects in Ceramic Rolling Elements

Abstract

Hybrid ceramic bearings consisting of steel rings with silicon nitride balls are now being manufactured on a commercial basis for use in high performance systems. The ceramic rolling elements should be capable of withstanding cyclic contact stresses of up to 4 GPa in order to give the required rolling contact fatigue performance. Surface quality must therefore be guaranteed in terms of freedom from both material and processing faults. High sensitivity fluorescent penetrants are capable of detecting fine surface breaking defects and have been adapted together with different imaging techniques for the routine inspection of ball surfaces.