Boosting the High Performance of BiFeO3-BaTiO3 Lead-Free Piezoelectric Ceramics: One-Step Preparation and Reaction Mechanisms

Yu-Cheng Tang; Yang Yin; Ai-Zhen Song; Huan Liu; Rui Zhang; Shi-Jie Zhong; He-Zhang Li; Bo-Ping Zhang

doi:10.1021/acsami.2c06164

Boosting the High Performance of BiFeO₃-BaTiO₃ Lead-Free Piezoelectric Ceramics: One-Step Preparation and Reaction Mechanisms

ACS Appl Mater Interfaces. 2022 Jul 13;14(27):30991-30999. doi: 10.1021/acsami.2c06164. Epub 2022 Jun 27.

Authors

Yu-Cheng Tang¹, Yang Yin¹, Ai-Zhen Song¹, Huan Liu¹, Rui Zhang¹, Shi-Jie Zhong¹, He-Zhang Li², Bo-Ping Zhang¹

Affiliations

¹ School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing, China.
² National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.

PMID: 35759732
DOI: 10.1021/acsami.2c06164

Abstract

One of the notorious problems in BiFeO₃-based piezoelectric ceramics is how to limit the formation of Bi₂₅FeO₃₉ and Bi₂Fe₄O₉ impurities to achieve excellent piezoelectric performance. In this study, a one-step preparation technology, namely, excluding PVA, calcining, and sintering are completed in one step, instead of three steps in the ordinary sintering method, is developed to prepare BiFeO₃-xBaTiO₃ (BF-xBT) ceramics. The significance of this one-step method is that the thermodynamically unstable region of BiFeO₃ is successfully avoided based on the Gibbs free energy of BiFeO₃, Bi₂₅FeO₃₉, and Bi₂Fe₄O₉. Benefiting from preventing the formation of Bi₂₅FeO₃₉ and Bi₂Fe₄O₉ impurities, the resultant ceramics show dense structures, macroscopic stripe domains, and a small number of island domains and display saturated P-E curves, sharp I-V characteristics, butterfly-shape S-E loops, and good piezoelectric properties (d₃₃ = 174-199 pC/N; T_C = 494-513 °C). By analyzing X-ray diffraction patterns of BF-xBT (0 ≤ x ≤ 1) powders at different calcination temperatures (T_cal), the different reaction mechanisms between 750 °C ≤ T_cal ≤ 900 °C and 950 °C ≤ T_cal ≤ 1000 °C are revealed. When 750 °C ≤ T_cal ≤ 900 °C, Bi³⁺ diffuses into Fe₂O₃ particles to form BiFeO₃ and Bi₂₅FeO₃₉ and then reacts with BaTiO₃; in this temperature range, the formed Bi₂₅FeO₃₉ is hard to eliminate. At 950 °C ≤ T_cal ≤ 1000 °C, Bi³⁺ and Fe ions simultaneously diffuse into BaTiO₃ to form BF-xBT, which is beneficial to preventing the formation of Bi₂₅FeO₃₉ and the improvement of performance.

Keywords: BiFeO3-BaTiO3; eliminate impurities; one-step preparation; piezoelectric ceramics; reaction mechanism.