Large-strain bismuth titanate sodium-based piezoelectric ceramics with enhanced temperature stability

• Published in: Journal of alloys and compounds 2024-10, Vol.1003, p.175554, Article 175554
• Main Authors: Dong, Gensheng, Li, Qi, Zhao, Yaoting, Liu, Ruihang, Zhang, Xiaofang, Li, Chungang, Lin, Xiujuan, Yang, Changhong, Huang, Shifeng
• Format: Article
• Language: English
• Subjects: Bismuth titanate sodium; Relaxor ferroelectric; Strain; Temperature stability
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.175554

Bi0.5Na0.5TiO3-based ceramics are chemically modified to easily generate large strains, which have been widely studied in the field of lead-free piezoelectric materials and actuators. However, the large temperature dependence of their electrically induced strains limits the practical applications. In this paper, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3-x wt%Sb2O3 (BNBT6-x wt%Sb2O3) lead-free ceramics were prepared by the conventional solid-phase method. When x = 0.6, a strain of 0.47 % was obtained at room temperature, and the strain fluctuation was only 10.1 % over a wide temperature range from 20℃ to 140℃. Furthermore, the strain essentially did not decay after 105 cycles, which had high temperature stability and fatigue stability while maintaining a large strain. The large strain and excellent fatigue performance are attributed to the reversible transition between the relaxor and ferroelectric state under the applied electric field. The remarkable stability of strain across temperatures was attributed to a synergistic interplay between two opposing effects: the negative temperature dependence of lattice distortion caused by the electric field, and the positive temperature dependence of the resulting strain itself. This interplay was believed to be facilitated by the presence of disordered and short-range nanodomains within the material. The present study achieved excellent comprehensive performance in strain and thermal stability, which helps to promote the development and applicability of lead-free actuators over a wide temperature range. •A large strain is 0.47 % with a fluctuation of only 10.1 % between 20℃ to 140℃ is achieved.•Ferroelectric relaxor temperature (TF-R) shifts towards room temperature with the addition of Sb2O3.•The evolution from microdomain to nanodomain enhances strain response.