Effects of electrolysis of water on the properties of soft lead zirconate titanate piezoelectric ceramics

Water-induced degradation in soft lead zirconate titanate (PZT) piezoelectric ceramics has been studied using electrochemical hydrogen charging, in which the silver electrodes of the piezoelectric ceramics is made a cathode in a 0.01 M NaOH solution to evolve hydrogen by electrolysis of water. It is found that with increasing hydrogen charging time, the impedance at the resonance frequency Zr increases, and the difference between the resonance and anti-resonance frequency (fa − fr) decreases. The dielectric permittivity and piezoelectric coefficient d33 decreases while the dielectric loss increases. I–V measurement shows that the resistivity decreases after hydrogen charging. These degradation behaviors in the soft piezoelectric ceramics can be explained as hydrogen incorporating into the lattice and forming hydroxy (OH−) bonds in the perovskite structure, which restrains the Ti ions from switching. The soft piezoelectric ceramics is partially depolarized after hydrogen charging which is quite different from that of hard lead zirconate titanate piezoelectric ceramics.