Li Pei, Jiang Renhui, Zhao Ligong, Peng Huayu, Zhao Peili, Jia Shuangfeng, Zheng He, Wang Jianbo
School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
Suzhou Institute of Wuhan University, Suzhou, Jiangsu 215123, China.
Inorg Chem. 2021 Dec 6;60(23):18199-18204. doi: 10.1021/acs.inorgchem.1c02839. Epub 2021 Nov 13.
Applying transmission electron microscopy, the phase instability in potassium tungsten bronze (KWO, 0.18 < < 0.57) induced by heating was investigated. The atomistic phase transition pathway of monoclinic KWO → hexagonal KWO (0.18 < < 0.20) → cubic WO induced by cationic defects (K and W vacancies) was directly revealed. Unexpectedly, a K-rich tetragonal KWO (0.40 < < 0.57) phase would nucleate as well, which may result from the blockage of K diffusion at the grain boundaries. Our results point out the critical role of the cationic defects in mediating the crystal structures in KWO, which provide reference to rational structural design for extensive high-temperature applications.
应用透射电子显微镜，研究了加热引起的钨青铜酸钾（KWO，0.18＜ ＜0.57）中的相不稳定性。直接揭示了由阳离子缺陷（K和W空位）诱导的单斜KWO→六方KWO（0.18＜ ＜0.20）→立方WO的原子相转变途径。出乎意料的是，富K的四方KWO（0.40＜ ＜0.57）相也会成核，这可能是由于晶界处K扩散受阻所致。我们的结果指出了阳离子缺陷在介导KWO晶体结构中的关键作用，为广泛的高温应用的合理结构设计提供了参考。
