Phase evolution of (K, Na)NbO3 powder prepared by high temperature mixing under hydrothermal conditions--颗粒学报PARTICUOLOGY

Bai, L., Zhu, K., Qiu, J., Ji, H., & Su, L. (2010). Phase evolution of (K, Na)NbO3 powder prepared by high temperature mixing under hydrothermal conditions. Particuology, 8(5), 477-481. https://doi.org/10.1016/j.partic.2010.05.007

Phase evolution of (K, Na)NbO₃ powder prepared by high temperature mixing under hydrothermal conditions

Lin Bai, Kongjun Zhu^*, Jinhao Qiu, Hongli Ji, Likui Su

The Aeronautical Key Laboratory for Smart Materials and Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

10.1016/j.partic.2010.05.007

Volume 8, Issue 5, October 2010, Pages 477-481

Received 11 September 2009, Revised 5 November 2009, Accepted 19 May 2010, Available online 29 June 2010.

E-mail: kjzhu@nuaa.edu.cn

Highlights

Abstract

(Na, K)NbO₃ (KNN) powders were successfully prepared by high temperature mixing method (HTMM) under hydrothermal conditions to study the effect of reaction time on the formation of KNN for three K⁺/(K⁺ + Na⁺) ratios of 0.6, 0.7 and 0.8. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), to show the change of phase and morphology of the as-prepared particles with the K⁺/(K⁺ + Na⁺) molar ratio in the solution. Pure Na-rich KNN monoclinic phase and pure K-rich KNN orthorhombic phase could be obtained quickly after mixing the solutions at high temperature when the K⁺/(K⁺ + Na⁺) molar ratio was either 0.6 or 0.8. When the K⁺/(K⁺ + Na⁺) molar ratio was 0.7, however, the K-rich KNN orthorhombic phase grain formed first, followed by the Na-rich KNN monoclinic phase grain, with the two phases coexisting in the final product.

Graphical abstract

Keywords

(Na, K)NbO₃; Hydrothermal conditions; High temperature mixing method; Phase evolution

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