Heating rate effect on dielectric, ferroelectric and piezoelectric properties of Bi<inf>0.45</inf>La<inf>0.05</inf>Na<inf>0.40</inf>K<inf>0.10</inf>Ti<inf>0.98</inf>Zr<inf>0.02</inf>O<inf>3</inf> Pb-free piezoelectric ceramic for actuator applications

Abstract

© 2019, © 2019 Taylor & Francis Group, LLC. In this present work, the effect of heating/coolling rate on the electrical properties such as ferroelectric, dielectric and electrostrictive properties of Pb-free Bi0.45La0.05Na0.40K0.10-Ti0.98Zr0.02O3 or BLNKZT piezoelectric ceramics has been systematically investigated. The BLNKZT ceramics were prepared via a conventional solid state reaction method and sintered at 1125 °C for 2 h, which applied the heating/cooling rates of 5, 10 and 15 °C/min in order to clarify the optimal parameter for densification and good electrical properties. The XRD pattern exhibited a complete single perovskite structure with a pseudo-cubic phase at the rate of 5 °C/min sample and tranformed to tetragonal-rich phase at the rate of 15 °C/min. The SEM micrograph of all BLNKZT ceramics showed a cubic-like grain shape. The P-E hysteresis loop was measured at the temperatures ranging from −40 to 120 °C. With increasing temperature, the Pr and Ec values distinctly decreased and the P-E loops tended to deform and showed pinch loops. The maximum strain (Smax) value of 0.10% and calculated normalized strain (d*33) of 167 pm/V (measured at 60 kV/cm) were obtained for ceramic sintered with the heating/cooling rates of 5 °C/min.