Surface Wave Acoustic Microscopy for Rapid NDE of Silicon Nitride Balls

Ceramic hybrid bearings have many excellent performance characteristics such as heat resistance, extended life, light weight, lower thermal expansion, electrical non-conductance, and thus become the top choice of rolling bearings for the F135 and F136 engines for the new generation Joint Striker Fighter F-35. The main concern in using ceramic materials for bearing applications is their reliability, because small defects in the ceramic (silicon nitride) ball can cause catastrophic failure of the bearing and are particularly prejudicial when they are located close to the surface. The existing techniques, however, can not simultaneously satisfy the requirements regarding the inspection cost, speed, resolution, and defect location (surface and subsurface). In this proposal, Intelligent Automation Inc. (IAI) is developing an innovative Surface Wave Acoustic Microscopy (SWAM) inspection system for rapid inspection of small defects on the surface or subsurface of silicon nitride balls. BENEFIT: The SWAM prototype that can provide rapid inspection of small defects in a ceramic ball could be the first standalone product. Hybrid bearings using silicon nitride balls as the rolling elements have been identified as the top choice for the next generation of high performance engines. The proposed technology has potential to meet the needs for 100% inspection of bearing balls in a rapid and cost effective manner. Therefore, the commercialization potential of this technique is huge.