Abnormal piezoelectric properties of acceptor doped 0.75BF-0.25BT lead-free ceramics for application in atomizer

Ecologically sustainable hard type piezoelectric ceramics are highly demanded for high power transducer applications in replacing lead-based piezoelectric ceramics. In this study, MnO was proposed as acceptor dopant to modify the electric properties of 0.75BiFeO₃-0.25BaTiO₃ piezoelectric ceramics. Results showed that MnO doping reduced the lattice distortion of rhombohedral phase and facilitated the formation of pseudo cubic phase of 0.75BiFeO₃-0.25BaTiO₃ system. Moreover, it caused the diversity of domain morphology and reduced the domain size as well. XPS analysis indicated that Mn²⁺ ions suppressed the transition from Fe³⁺ ions to Fe²⁺ ions and gave rise to the increase of oxygen vacancies. Accordingly, the introduction of MnO synergistically increases the d₃₃, K_p, and Q_m and lowers the tanδ of 0.75BiFeO₃-0.25BaTiO₃ ceramics. The abnormal enhancement in hard type properties is ascribed mainly to the increase of extrinsic contribution rather than the pinning effect arising from oxygen vacancies. Finally, based on an optimal 0.75Bi(Fe_0.985Mn_0.015)O₃-0.25BaTiO₃ system, an atomizer prototype was fabricated. The remarkable atomization effect suggests a competitive potential of 0.75BF-0.25BT ceramic for transducer application.