摘要
Among the lead-free piezoceramics,(1-x)BiFeO_(3)-xBaTiO_(3)(BF-BT)is considered a promising candidate for high-temperature piezoelectric materials owing to its high Curie temperature(TC>400℃)and good electromechanical properties.In this work,the hydrothermal synthesis method was used to prepare the precursor powders of BiFeO_(3)and BaTiO_(3),and then the mixed powder compacts with the chemical composition of 0.7BF–0.3BT were sintered under pressureless conditions.The influence of the hydrothermal reaction times(12–24 h)of BiFeO_(3)on the structures and electric properties of the sintered ceramics was instigated.First,all the samples synthesized with the tetragonal BaTiO_(3)and BiFeO_(3)powders were identified with relatively stable dielectric properties.As the hydrothermal reaction time to synthesize BiFeO_(3)increased,the dielectric properties as well as the temperature stability of the 0.7BiFeO_(3)–0.3BaTiO_(3)ceramics also improved.At the condition of a hydrothermal reaction time of 24 h,the sample obtained possesses both the lowest temperature coefficient of dielectric constant(Tkε=1.53×10^(-2)=℃between RT and 300℃)and the highest Curie temperature(TC?471℃at 100 kHz).Moreover,at high temperatures,it exhibits a higher AC impedance than others.The calculating result based on the resistive constant-phase-element model(R-CPE)circuit model showed that the grain boundary of the 0.7BF–0.3BT ceramics contributes more resistance to the conductivity at high temperatures.In summary,the hydrothermal reaction proved to be a useful way that achieves the preparation of single-phase 0.7BF–0.3BT ceramics with improved electrical properties.
基金
funded by the Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion(No.MATEC2022KF001)
as well as the project for cultivating High-level Talents and National Natural Science Foundation at the Chengdu University(No.Z1350).
