J. Mater. Sci. Technol. ›› 2024, Vol. 172: 255-263.DOI: 10.1016/j.jmst.2023.06.043

• Research Article • Previous Articles    

Comprehensive optimization of piezoelectric coefficient and depolarization temperature in Mn-doped Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-BaTiO3 lead-free piezoceramics

Huashan Zhenga, Enwei Suna,*, Huajie Luob, Xiaoyu Zhangc, Yixiao Yanga, Bin Yanga,*, Rui Zhanga, Shantao Zhangc, Wenwu Caoa,d   

  1. aCondensed Matter Science and Technology Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, China;
    bAdvanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China;
    cNational Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, College of Engineering and Applied Science & Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China;
    dDepartment of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States of America
  • Received:2023-03-20 Revised:2023-05-11 Accepted:2023-06-21 Published:2024-02-10 Online:2023-08-11
  • Contact: *E-mail addresses: sunew@hit.edu.cn (E. Sun), binyang@hit.edu.cn (B. Yang)

Abstract: Lead-free Bi0.5Na0.5TiO3 (BNT) piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures. But the improvement of piezoelectric coefficient (d33) is usually accompanied by a huge sacrifice of depolarization temperature (Td). In this work, a well-balanced performance of d33 and Td is achieved in MnO2-doped 0.79(Bi0.5Na0.5TiO3)-0.14(Bi0.5K0.5TiO3)-0.07BaTiO3 ternary ceramics. The incorporation of 0.25 mol% MnO2 enhances the d33 by more than 40%, while Td remains almost unchanged (i.e., d33=181 pC/N, Td=184 °C). X-ray diffraction (XRD) shows that an appropriate fraction of the small axis-ratio ferroelectric phase (pseudo-cubic, Pc) coexists with the long-range ferroelectric phase (tetragonal, T) under this MnO2 doping. Piezoelectric force microscopy (PFM) has revealed a special domain configuration, namely large striped and layered macro domains embedded with small nanodomains. This study provides a distinctive avenue to design BNT-based piezoelectric ceramics with high piezoelectric performance and temperature stability.

Key words: BNT-BKT-BT ceramics, Mn doping, Piezoelectric, Depolarization temperature, Phase structure