A cylindrical micro ultrasonic motor fabricated by improved hydrothermal method

A PZT thin film which was utilized to a micro ultrasonic motor was improved by a single process hydrothermal method. An earlier reported hydrothermal method consisted of two linked processes. Our new process has only single process. Hence, less distribution of chemical components contributed to higher efficiency of the stator transducer. The output torque of the micro ultrasonic motor deposited by the single process hydrothermal method was measured. The output torque was 7.0 mu Nm and the maximum revolution speed was 880 rpm at 15 Vp-p driving voltage. Furthermore, the relationship between KOH concentration and film performance indicated that there is ample room for further improvement in the hydrothermal method.