Significant impact of TiO <sub>2</sub> purity on the phase structure and electrical properties of BiFeO <sub>3</sub> –BaTiO <sub>3</sub> lead‐free piezoelectric ceramics
Xiaoxin Chen, Hailan Qin, Hongtian Li, Yuxiao Du, Shenghao Wang, Peifeng Li, Yongming Hu, Laijun Liu, Jianwei Zhao, Dawei Wang
Abstract
Abstract In many studies, the properties of BiFeO 3 –BaTiO 3 (BF–BT) ceramics vary greatly using different raw reagents, which makes it challenging to obtain reliable and repeatable properties of BF–BT‐based devices. In this work, 0.7BiFeO 3 –0.3BaTiO 3 (0.7BF–0.3BT) ceramics were fabricated by a conventional solid‐phase synthesis using TiO 2 reagents with varied purities of 98%, 99%, 99.9%, and 99.99%, respectively. The phase structure, microstructure, ferroelectric, and piezoelectric properties were comprehensively studied. All compositions of the ceramics exhibit a pseudo‐cubic phase perovskite structure, and the fraction of the rhombohedral phase increases with increasing the TiO 2 purity. Additionally, backscattered electron images and energy‐dispersive spectroscopy revealed an obvious core–shell structure within grains. In particular, the 0.7BF–0.3BT ceramics prepared with 98% purity TiO 2 exhibited superior ferroelectric and piezoelectric properties, d 33 ∼ 220 pC/N and ∼ 230 pm/V. The ceramics prepared with higher purity TiO 2 suffered from severe leakage conduction, which can be well addressed by adding excess TiO 2 . Our work reveals the importance of different grades of purity TiO 2 on the electrical properties of BF–BT ceramics.