Functionally Graded Piezoelectric Ceramics for Ultrasonic Transducers
Functionally graded piezoelectric ceramics (FGM) plates are attractive due to their ability to broaden the frequency bandwidth of the ultrasonic transducers. A resistivity gradient La-doped Lead Zirconate Titanate/Al-doped Zinc Oxide (La-PZT/Al-ZnO) piezoelectric ceramics plate was developed using a powder metallurgical process. Grading of the piezoelectric modulus across the plate was experimentally confirmed by the electrical impedance analysis and its gradient distribution was characterized using the profile-technique. The distribution of Zn2+ ions in the PZT region was examined using EPMA, XRD and SEM/EDX, respectively. Analysis results show that the gradient distributions of structural and electrical properties inside the FGM plate are mainly caused by the diffusion and aggregation of Zn2+ ions in the PZT layer. The functionally graded piezoelectric ceramics plate presented here will be useful for broadening the frequency bandwidth of piezoelectric transducers.
Wei Pan and Jianghong Gong
D. R. Jin et al., "Functionally Graded Piezoelectric Ceramics for Ultrasonic Transducers", Key Engineering Materials, Vols. 336-338, pp. 2609-2612, 2007