Fabrication of 1-3 Piezocomposites via Soft Mold Method for High-frequency Ultrasound Transducer

The high-frequency ultrasonic technology has been widely used for the fine structures medical imaging of skin, eye and vessel as its high spatial resolution. 1-3 piezocomposite plays an important part in the high frequency transducer owing to the excellent electromechanical coupling properties of this material even at high frequency. However, its industrial applications were limited by the inefficient fabrication methods and expensive equipment, such as mechanical cutting-filling and plasma/laser etching. In this work, a low-cost and novel soft mold method was developed to fabricate 1-3 piezoelectric composites with high electromechanical coupling coefficient kt for high frequency ultrasound transducers. The process of soft mold filling, hot-pressed sintering PZT pillars and epoxy curing was ruly carried out. Then, a series of samples with different thicknesses were fabricated and characterized. It demonstrates that the fabricated PZT pillars with pure rhombohedral phase are homogeneous.Besides, the length to diameter ratio of sintered pillars is 10 : 1 and the kt of the 1-3 piezocomposite reaches as high as 64% for the 30-50 MHz high frequency transducer. The result indicates that the soft mold method is an economical and effective way to fabricate the 1-3 piezoelectric composites for medical and biological imaging in high frequency ultrasound applications.