Metal Particle Composite Hardening in Ba_0.85C_a0.15Ti_0.90Zr_0.10O₃ Piezoceramics

Hard-type piezoceramics are key materials in high-power transducers and transformers. Acceptor doping is the most widely used piezoelectric hardening approach, but the mobility of oxygen vacancies at large electric fields or at high temperatures inevitably leads to the deterioration of hardening performance. The present study proposes a new hardening method associated with intragranular metal particles for achieving strong pinning of ferroelectric domain walls. Highly effective piezoelectric hardening via intragranular Ag particles in Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃ ceramic is realized, where the mechanical quality factor Q_m and the coercive field E_c increase by 170% and 53%, respectively. The Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃/0.10Ag sample features a larger high-power mechanical quality factor than the pure Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃. Moreover, the piezoelectric properties (d₃₁ and k₃₁) of the Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃/0.10Ag sample show exceptional stability with the increase in vibration velocity. This composite approach of introducing metal particles can be considered as a generic hardening method and can be extended to other ferroelectric systems.