Flexible Ultrasonic Transducers by Automatic Spray Coating for Non-Destructive Testing

Flexible ultrasonic transducers have been demanded growing for non-destructive testing (NDT). Pb(Zr,Ti)O-3/Pb(Zr,Ti)O-3(PZT/PZT) sol-gel composite ultrasonic transducers made by spray coating technique have flexibility. However, in this method, it required operator's experience and not suitable for mass production due to film quality individual difference. Therefore, automatic spray coating is desired for flexible ultrasonic transducer. In automatic spray coating method, spray coating process were performed by automatic spray coating machine, not human hand to fabricate uniform quality PZT/PZT films. In this study, PZT/PZT sol-gel composite thin films were fabricated onto thin stainless steel substrates in manual spray coating method and automatic spray coating method. After flexible ultrasonic transducer fabrication, ultrasonic measurements were carried out for aluminum substrate as flat surface and steel pipe as curved surface. As a result, ultrasonic transducer made by automatic spray coating method showed comparable with the one made by manual spray coating method. These results indicate steady potential of flexible ultrasonic transducer by automatic spray coating method.