Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios

The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol–gel solution to PZT powder in the composite solution. Both the remanent polarization, P _r, and transverse piezoelectric coefficient, e _{31, f} , increase with increasing proportion of the sol–gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm², a dielectric constant of 450 (at 1 kHz), and e _{31, f} =−2.8 C/m². Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm², a dielectric constant of 1250 (at 1 kHz) and e _{31, f} =−5.8 C/m².