Diffused Phase Transition Boosts Thermal Stability of High‐Performance Lead‐Free Piezoelectrics |
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| Authors: | Fang‐Zhou Yao Ke Wang Wook Jo Kyle G. Webber Timothy P. Comyn Jing‐Xuan Ding Ben Xu Li‐Qian Cheng Mu‐Peng Zheng Yu‐Dong Hou Jing‐Feng Li |
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| Affiliation: | 1. State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, P.R. China;2. School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea;3. Department of Materials Science, University of Erlangen‐Nürnberg, Erlangen, Germany;4. Institute for Materials Research, University of Leeds, Leeds, UK;5. Department of Materials Science and Engineering, Beijing University of Technology, Beijing, P. R. China |
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| Abstract: | High piezoelectricity of (K,Na)NbO3 (KNN) lead‐free materials benefits from a polymorphic phase transition (PPT) around room temperature, but its temperature sensitivity has been a bottleneck impeding their applications. It is found that good thermal stability can be achieved in CaZrO3‐modified KNN lead‐free piezoceramics, in which the normalized strain d 33* almost keeps constant from room temperature up to 140 °C. In situ synchrotron X‐ray diffraction experiments combined with permitivity measurements disclose the occurrence of a new phase transformation under an electrical field, which extends the transition range between tetragonal and orthorhombic phases. It is revealed that such an electrically enhanced diffused PPT contributed to the boosted thermal stability of KNN‐based lead‐free piezoceramics with high piezoelectricity. The present approach based on phase engineering should also be effective in endowing other lead‐free piezoelectrics with high piezoelectricity and good temperature stability. |
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| Keywords: | lead‐free niobate phase transition piezoelectric temperature stability |
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