Lead Zirconate Titanate Nanotube Composite for Ultrasound Transducer Application

Lead Zirconate Titanate (PbZr_1−xTi_xO₃, PZT) is a high performance piezoelectric material which is widely used for making ultrasound transducers. However, pure PZT suffered from high acoustic impedance and crosstalk effect, which deteriorate their performances. To solve these problems, people developed micro fiber PZT composite. As restricted by the fabrication method, like dicing, the size of PZT micro fibers are usually on the order of 10s micros. In this paper, we are going to introduce a PZT nanotube composite, in which the size of active material is on the order of nanometers. To fabricate the PZT nanotube composite, we used a template assistant method. First an anodic aluminum oxide (AAO) template was made by two step anodic process. Then PZT nanotube composite was made by wetting the AAO template with PZT sol-gel. Following, top and bottom electrodes were made by silver paste. After fabrication, hysteresis loops were measured to verify the piezoelectricity property of this nanotube composite. Then the impedance of the composite transducer was measured by a network analyzer. Resonant frequency of the transducer was found by the impedance data. This nanotube composite based transducer could theoretically reduce or even eliminate the crosstalk effect, since the diameter of nanotube is much smaller than half wave length of ultrasound. So an improved performance of PZT nanotube composite based ultrasound transducer could be expected.