氧化铁纳米链在透射电子显微镜加热过程中的还原反应和致密化
Reduction reactions and densification during TEM heating of iron oxide nanochains.
作者信息
Bonifacio Cecile S, Das Gautom, Kennedy Ian M, van Benthem Klaus
机构信息
Department of Materials Science and Engineering, University of California Davis, 1 Shields Ave., Davis, California 95616, USA.
Department of Mechanical and Aerospace Engineering, University of California Davis, 1 Shields Ave., Davis, California, 95616, USA.
出版信息
J Appl Phys. 2017 Dec 21;122(23):234303. doi: 10.1063/1.5004092.
The reduction reactions and densification of nanochains assembled from -FeO nanoparticles were investigated using transmission electron microscopy (TEM). Morphological changes and reduction of the metal oxide nanochains were observed during TEM annealing through simultaneous imaging and quantitative analysis of the near-edge fine structures of Fe L absorption edges acquired by spatially resolved electron energy loss spectroscopy. A change in the oxidation states during annealing of the iron oxide nanochains was observed with phase transformations due to continuous reduction from FeO over FeO, FeO to metallic Fe. Phase transitions during the heating experiments were accompanied with morphological changes in the nanochains, specifically rough-to-smooth surface transitions below 500 °C, neck formation between adjacent particles around 500 °C, and subsequent neck growth. At higher temperatures, coalescence of FeO particles was observed, representing densification.
利用透射电子显微镜（TEM）研究了由-FeO纳米颗粒组装而成的纳米链的还原反应和致密化过程。通过对空间分辨电子能量损失谱获取的Fe L吸收边近边精细结构进行同步成像和定量分析，在TEM退火过程中观察到了金属氧化物纳米链的形态变化和还原情况。随着氧化铁纳米链从FeO经FeO、FeO持续还原为金属Fe而发生相变，观察到了退火过程中氧化态的变化。加热实验中的相变伴随着纳米链的形态变化，具体表现为低于500°C时表面从粗糙到光滑的转变，500°C左右相邻颗粒之间形成颈部，随后颈部生长。在较高温度下，观察到FeO颗粒的聚结，这代表着致密化。
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