Liu Yi-Xuan, Qu Wanbo, Thong Hao-Cheng, Zhang Yang, Zhang Yunfan, Yao Fang-Zhou, Nguyen Trong Nghia, Li Jia-Wang, Zhang Mao-Hua, Li Jing-Feng, Han Bing, Gong Wen, Wu Haijun, Wu Chaofeng, Xu Ben, Wang Ke
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
Adv Mater. 2022 Jul;34(29):e2202558. doi: 10.1002/adma.202202558. Epub 2022 Jun 13.
Defect engineering is a well-established approach to customize the functionalities of perovskite oxides. In demanding high-power applications of piezoelectric materials, acceptor doping serves as the state-of-the-art hardening approach, but inevitably deteriorates the electromechanical properties. Here, a new hardening effect associated with isolated oxygen vacancies for achieving well-balanced performances is proposed. Guided by theoretical design, a well-balanced performance of mechanical quality factor (Q ) and piezoelectric coefficient (d ) is achieved in lead-free potassium sodium niobate ceramics, where Q increases by over 60% while d remains almost unchanged. By atomic-scale Z-contrast imaging, hysteresis measurement, and quantitative piezoresponse force microscopy analysis, it is revealed that the improved Q results from the inhibition of both extrinsic and intrinsic losses while the unchanged d is associated with the polarization contributions being retained. More encouragingly, the hardening effect shows exceptional stability with increasing vibration velocity, offering potential in material design for practical high-power applications such as pharmaceutical extraction and ultrasonic osteotomes.
缺陷工程是一种成熟的用于定制钙钛矿氧化物功能的方法。在对压电材料要求较高的高功率应用中，受主掺杂是目前最先进的硬化方法，但不可避免地会降低机电性能。在此，提出了一种与孤立氧空位相关的新硬化效应，以实现性能的良好平衡。在理论设计的指导下，无铅铌酸钾钠陶瓷实现了机械品质因数（Q）和压电系数（d）的良好平衡性能，其中Q增加了60%以上，而d几乎保持不变。通过原子尺度的Z衬度成像、滞后测量和定量压电力显微镜分析表明，Q的提高源于外在和内在损耗的抑制，而d不变与极化贡献得以保留有关。更令人鼓舞的是，随着振动速度的增加，这种硬化效应表现出卓越的稳定性，在药物提取和超声骨刀等实际高功率应用的材料设计中具有潜力。
