Elaboration process and study of Nb-Ni substituted PZT ceramics with high d33 and εr coefficients

PZT (lead zirconate titanate) ceramics with high Nb-Ni substitution (about 40%) have been prepared according to a solid process and a wet chemical process by coprecipitated oxalates. Precipitation conditions were carefully examined because some variations in the properties of sintered ceramics were observed. The best conditions of thermal decomposition, thermal treatment, and sintering are determined for the PbZr_0.23Ti_0.37 (Nb_2/3Ni_1/3 )_0.4O₃ composition. Hot-pressing sintering is shown to improve the electrical and mechanical properties of the ceramics and to allow the achievement of material with a large value of ε_r (5300), and high d₃₃ and k₃₃ constants, along with a not very significant temperature variation between 25 and 125°C in view of a 180°C Curie temperature. These properties make this material promising for high-frequency medical ultrasonic imaging transducers