High-frequency and high-temperature electromechanical performances of new PZT-PNN piezoceramics

Ferroelectric ceramics based on a solid solution between a PZT ferroelectric phase and a relaxor phase from the lead-nickel-niobium system are characterised. Two different mixed-oxide routes have been used in order to compare the dielectric, piezoelectric and elastic properties of the two ceramics obtained. The characterisation method is based on measurements of the electrical impedance of samples as a function of frequency and allows the determination of the thickness mode resonance parameters. Results are given as a function of frequency (5 to over 25 MHz) and temperature (ambient to over 230 degreesC). Finally, several simulations, using a K.L.M. model, of medical transducers are performed. The results show that the ceramic is well adapted for medical imaging applications, in particular for array transducer configurations. (C) 2001 Elsevier Science Ltd. All rights reserved.