Relaxor ferroelectricity and elevated thermal expansion behaviour of (1−x)Bi0.5Na0.5TiO3-xBaSnO3 lead-free piezoelectric ceramics

• Published in: Journal of alloys and compounds Vol. 991; p. 174566
• Main Authors: Tian, Yongshang, Ma, Mingyang, Li, Shuiyun, Yan, Chenbo, Ji, Xiang, Wu, Haitao, Wang, Jinshuang, Jing, Qiangshan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.07.2024
• Subjects: BaSnO3 dopants; BNT-based ceramics; Diffused phase transition; Relaxor ferroelectricity; Thermal expansion behaviour; Relaxor ferroelectricity; Diffused phase transition; Thermal expansion behaviour; BNT-based ceramics; BaSnO3 dopants
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2024.174566

The study on piezoelectric and ferroelectric properties of sodium bismuth titanate-based materials is essential for piezoelectric electronic components. In this study, a series of lead-free relaxor ferroelectric (1−x)Bi0.5Na0.5TiO3-xBaSnO3 (BNT-xBS) ceramics were prepared by a conventional solid-state reaction method. The phase performance, fracture morphologies, permittivity, ferroelectricity, piezoelectricity, and thermal expansion for various BS contents (x) were systematically studied. With an increase in x, the phase transition from R3c to P4bm, and the grain size marginally decreased from 1.79 to 1.51 μm. Meanwhile, the degree of dielectric relaxor and diffused phase transition improved, and the ferroelectricity and piezoelectricity initially increased and then decreased. The optimal electrical properties of Pr = 41.6 μC/cm2, d33 = 167.8 pC/N, and kp = 0.318 were observed at x = 0.06. The paper discusses how site disorder, long-range electric dipole ordering, and grain size influence various electrical properties. The mechanism of the thermal expansion behaviour was investigated based on Born-Lande theory. This study could serve as a landmark for studying multifunctional BNT-based piezoelectric materials for potential energy-harvesting devices. •BaSnO3 could induce phase transition of R3c to P4bm in BNT-based ceramics.•Ceramics exhibited a high densification with a grain size of approximately 1.7 μm.•Diffused phase transition and relaxor degree enhanced with increasing x.•Influencing factors of site and long-range electric dipole order were discussed.•Mechanism of thermal expansion behaviour was studied using Born-Lande theory.