Tang Yu-Cheng, Yin Yang, Song Ai-Zhen, Liu Huan, Zhang Rui, Zhong Shi-Jie, Li He-Zhang, Zhang Bo-Ping
School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing, China.
National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
ACS Appl Mater Interfaces. 2022 Jul 13;14(27):30991-30999. doi: 10.1021/acsami.2c06164. Epub 2022 Jun 27.
One of the notorious problems in BiFeO-based piezoelectric ceramics is how to limit the formation of BiFeO and BiFeO 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 BiFeO-BaTiO (BF-BT) ceramics. The significance of this one-step method is that the thermodynamically unstable region of BiFeO is successfully avoided based on the Gibbs free energy of BiFeO, BiFeO, and BiFeO. Benefiting from preventing the formation of BiFeO and BiFeO impurities, the resultant ceramics show dense structures, macroscopic stripe domains, and a small number of island domains and display saturated - curves, sharp - characteristics, butterfly-shape - loops, and good piezoelectric properties ( = 174-199 pC/N; = 494-513 °C). By analyzing X-ray diffraction patterns of BF-BT (0 ≤ ≤ 1) powders at different calcination temperatures (), the different reaction mechanisms between 750 °C ≤ ≤ 900 °C and 950 °C ≤ ≤ 1000 °C are revealed. When 750 °C ≤ ≤ 900 °C, Bi diffuses into FeO particles to form BiFeO and BiFeO and then reacts with BaTiO; in this temperature range, the formed BiFeO is hard to eliminate. At 950 °C ≤ ≤ 1000 °C, Bi and Fe ions simultaneously diffuse into BaTiO to form BF-BT, which is beneficial to preventing the formation of BiFeO and the improvement of performance.
基于铋铁氧体的压电陶瓷中一个臭名昭著的问题是如何限制铋铁氧体和铋铁氧体杂质的形成以实现优异的压电性能。在本研究中，开发了一种一步制备技术，即在一步中完成排除聚乙烯醇、煅烧和烧结，而不是普通烧结方法中的三步，以制备铋铁氧体-钛酸钡（BF-BT）陶瓷。这种一步法的意义在于基于铋铁氧体、铋铁氧体和铋铁氧体的吉布斯自由能成功避免了铋铁氧体的热力学不稳定区域。得益于防止铋铁氧体和铋铁氧体杂质的形成，所得陶瓷呈现致密结构、宏观条纹畴和少量岛状畴，并显示出饱和的电滞回线、尖锐的特性、蝶形回线和良好的压电性能（d33 = 174 - 199 pC/N；Tc = 494 - 513 °C）。通过分析不同煅烧温度（T）下BF-BT（0 ≤ x ≤ 1）粉末的X射线衍射图谱，揭示了750 °C ≤ T ≤ 900 °C和950 °C ≤ T ≤ 1000 °C之间不同的反应机制。当750 °C ≤ T ≤ 900 °C时，铋扩散到氧化铁颗粒中形成铋铁氧体和铋铁氧体，然后与钛酸钡反应；在该温度范围内，形成的铋铁氧体难以消除。在950 °C ≤ T ≤ 1000 °C时，铋和铁离子同时扩散到钛酸钡中形成BF-BT，这有利于防止铋铁氧体的形成和性能的提高。
