Enhancement of Piezoelectric Performance of Lead-Free NKN-Based Ceramics via a High-Performance Flux—NaFNb2O5

Authors

  • Cheng Liu,

    Corresponding author
    1. College of Physics and Information Technology, Shaanxi Normal University, Xi'an, Shaanxi, China
    • Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania
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  • Peng Liu,

    1. College of Physics and Information Technology, Shaanxi Normal University, Xi'an, Shaanxi, China
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  • Keisuke Kobayashi,

    1. Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania
    2. Materials R&D Department, R&D Laboratory, Taiyo Yuden Co., Ltd., Takasaki, Gunma, Japan
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  • Wei-guo Qu,

    1. Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania
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  • Clive A. Randall

    Corresponding author
    • Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania
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Authors to whom correspondence should be addressed. e-mails: chengliu328@gmail.com and car4@psu.edu

Abstract

x(NaF−0.5Nb2O5)−(1 − x)[(Na0.5K0.5)(Nb0.8Ta0.2)O3] (100xNN−NKNT) piezoelectric ceramics were fabricated to high densities above 97% when sintering at temperatures ~1200°C. Compared with pure (Na,K)NbO3 (NKN), dielectric constants of the NaFNb2O5 flux-doped NKNT ceramics were increased whereas dielectric losses remained low. High field polarization switching showed very square hysteresis loops, but the coercive fields were decreased through a “softening” doping effect induced by the flux. A Rayleigh analysis inferred that the extrinsic contribution from the domain wall dynamics was increased with the flux addition. Collectively, all the experimental observations suggested that NaFNb2O5 was, in part, soluble in the structure and highly suitable for obtaining a stable NKN system with improved piezoelectric performance.

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