Zhang Nan, Zheng Ting, Li Ning, Zhao Chunlin, Yin Jie, Zhang Yang, Wu Haijun, Pennycook Stephen J, Wu Jiagang
Department of Materials Science, Sichuan University, Chengdu 610065, P R. China.
Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.
ACS Appl Mater Interfaces. 2021 Feb 17;13(6):7461-7469. doi: 10.1021/acsami.0c21181. Epub 2021 Feb 5.
The piezoelectric constant () and converse piezoelectric coefficient (*) of a piezoelectric material are critically important parameters for sensors and actuators. Here, we simultaneously achieve a high of 595 ± 10 pC/N and a large * of ∼776 ± 20 pm/V in (K,Na)NbO (KNN)-based ceramics, which exceed those of PZT5H and PZT4 ceramics, presenting good potential for practical piezoelectric applications. Moreover, the ceramic exhibits a relaxor-like and diffuse dielectric behavior due to the occurrence of local heterogeneity. According to the experiments and atomic resolution polarization mapping by Z-contrast imaging, hierarchical architecture of nanodomains and even smaller polar nanoregions with multiphase coexistence caused by compositional modification is the structural origin of the enhanced piezoelectric properties in this work. This work would pave a practical way to future applications of lead-free KNN-based ceramics.
压电材料的压电常数（）和逆压电系数（*）对于传感器和致动器而言是至关重要的参数。在此，我们在基于（K，Na）NbO（KNN）的陶瓷中同时实现了高达595±10 pC/N的高压电常数和大约776±20 pm/V的大逆压电系数，这超过了PZT5H和PZT4陶瓷的相应值，展现出在实际压电应用中的良好潜力。此外，由于局部不均匀性的出现，该陶瓷呈现出类弛豫体和弥散介电行为。根据实验以及通过Z衬度成像进行的原子分辨率极化映射，由成分改性导致的具有多相共存的纳米畴和甚至更小的极性纳米区域的分级结构是本工作中压电性能增强的结构起源。这项工作将为基于无铅KNN的陶瓷的未来应用铺平一条切实可行的道路。
