钙钛矿LaNiO3热烧结过程中相转变机理的研究

钙钛矿LaNiO₃热烧结过程中相转变机理的研究

刘涵钰^#，朱 柳^#，张宇中，陈 越，史博文，胡 阳，彭 勇^*

（1. 兰州大学材料与能源学院&兰州大学电镜中心，甘肃兰州730000；2.兰州大学物理科学与技术学院，甘肃兰州730000；3.兰州大学化学化工学院&兰州大学电镜中心，甘肃兰州730000）

摘  要   本文针对钙钛矿结构的LaNiO₃在热烧结过程中物相转变机制，利用离位及原位电镜结合宏观光谱进行了观测和分析研究。实验结果表明，通过静电纺丝法制备的PVP/PAN/Ni(NO₃)₂/La(NO₃)₃前驱体纤维能够通过高温烧结形成LaNiO₃的钙钛矿结构。研究发现在温度作用下，晶体生长过程中碳聚合物基体不断受热分解，浸渍在聚合物基体上的金属离子受热与气氛中的氧结合，形成氧化物晶胚，呈现典型的奥斯瓦尔德熟化生长过程，在600℃左右，LaNiO₃的晶体相生成，随着温度的进一步升高，晶粒互相融合形成了纳米颗粒堆垛成的一维LaNiO₃纳米线。实验揭示了LaNiO₃纳米线的微观生长机制，为材料的生长调控和性能改性提供了思路。

关键词  钙钛矿结构；物相转变；奥斯瓦尔德熟化生长；原位电子显微学

中图分类号：076；0614；TG115. 21⁺5. 3  文献标识码：A   doi:10.3969/j.issn.1000-6281.2024.01.003

Study on phase formation process and doping modification of perovskite type composite oxide materials

LIU Han-yu^1#，ZHU Liu^1#，ZHANG Yu-zhong²，CHEN Yue¹，SHI Bo-wen¹，HU Yang³，PENG Yong^1*

（1. College of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou Gansu 730000；2. School of Physical and Technology of Lanzhou University, Lanzhou Gansu 730000；3. College of Chemistry and Chemical Engineering and Electron Microscopy Centre of Lanzhou University, Lanzhou Gansu 730000，China）

Abstract   This article focused on the phase transition mechanism of LaNiO₃ with a perovskite structure during the hot sintering process, which was observed and analyzed by ex-situ and in-situ electron microscopy combined with a macroscopic spectroscopy. The experimental results indicated that the precursor fibers of PVP/PAN/Ni(NO₃)₂/La(NO₃)₃ prepared by electrospinning formed a LaNiO₃ perovskite structure . Under the high-temperature sintering, the carbon polymer matrix was continuously decomposed during the crystal growth process. The metal ions immersed in the polymer matrix were heated and combined with oxygen in the atmosphere to form oxide crystal embryos, showing a typical Ostwald ripening growth process. At about 600 ℃, the LaNiO₃ crystal phase was generated. With the further increase of temperature, the grains fused with each other to form one-dimensional LaNiO₃ nanowires stacked with nanoparticles. The experiment revealed the micro growth mechanism of LaNiO₃ nanowires, providing ideas for the growth regulation and performance modification of materials.

Keywords  perovskite structure；phase transition；Oswald ripening mechanism；in-situelectron microscopy

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