Mechanical constitutive behavior and exceptional blocking force of lead-free BZT-xBCT piezoceramics

The free strain during unipolar electrical activation and the blocking stress are important figures of merit for actuator applications. The lead-free (1 − x)Ba(Zr0.2Ti0.8)O3−x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) system has been shown to display exceptional unipolar strain at room temperature, making it very attractive as an electroactive material for large displacement, low frequency actuation systems. In this work, the temperature- and composition-dependent blocking stress is measured with the proportional loading method. It was found that BZT-xBCT outperformed Pb(Zr1−xTix)O3 and Bi1/2Na1/2TiO3–based ceramics for electric fields up to 2 kV/mm.