Fabrication of (Bi0.5K0.5)TiO3 modified BaTiO3-Bi(Mg0.5Ti0.5)O3-BiFeO3 piezoelectric ceramics

• Published in: Journal of the European Ceramic Society Vol. 41; no. 7; pp. 4108 - 4115
• Main Authors: Khanal, Gopal Prasad, Fujii, Ichiro, Kim, Sangwook, Ueno, Shintaro, Wada, Satoshi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2021
• Subjects: (Bi0.5K0.5)TiO3; Bi-based; Lead-free; Piezoelectric strain constant (d33); relaxor-ferroelectrics; relaxor-ferroelectrics; (Bi0.5K0.5)TiO3; Bi-based; Piezoelectric strain constant (d33); Lead-free
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2021.02.015

The lead-free x(Bi0.5K0.5)TiO3-0.23BaTiO3-0.02Bi(Mg0.5Ti0.5)O3-(0.75-x)BiFeO3 piezoelectric ceramics (x = 0.05, 0.07, 0.09, and 0.11) were prepared by solid-state reaction method. The increase of (Bi0.5K0.5)TiO3 concentration revealed a decrease of dielectric maximum temperature (Tm), however, the values were higher than 420 °C. The Rietveld structure refinement for each composition showed pseudo-cubic symmetry and the rhombohedral distortion (90 - αF) was gradually decreased from 0.27° to 0.09° for x = 0.05 and 0.11, respectively. The saturation and remanent polarization were increased and a coercive field was decreased, while the critical exponent (γ) was increased from 1.407 (x = 0.07) to 1.821 (x = 0.11) revealing more relaxor-like behavior with higher (Bi0.5K0.5)TiO3 content. The remanent polarization, coercive field, and piezoelectric strain constant of 31.9 μC/cm2, 23.6 kV/cm, and 315 pm/V, respectively, obtained in the composition with x = 0.11 are significantly higher than those reported previously for other Bi-based piezoelectric ceramics with Tm>250 °C.