Ceramic Bearing Development, Vol 2. Development of Surface Acoustic Wave NDE forSilicon Nitride Balls

摘要

The Major Objective of the Development of a Surface Acoustic Wave NondestructiveEvaluation (NDE) Technique for Silicon Nitride Balls was to improve hybrid bearing reliability by the elimination of critical size flaws that cause early failures. A Surface Acoustic Wave NDE technique was developed for Norton Advanced Ceramics NBD-200 silicon nitride balls. System performance was verified on balls with both natural and artificial flaws. A production lot of NBD-200 balls was tested using this method. The production lot was sorted for fatigue testing at 2.9 MPa (420 KSI) contact stress at The Timken Co. Results suggest that the technique can readily identify certain life limiting flaws. However, fatigue testing of balls inspected with this technique showed no improvement in reliability.