کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1329938 | 978934 | 2007 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Formation of γ-Fe2O3 nanoparticles and vacancy ordering: An in situ X-ray powder diffraction study Formation of γ-Fe2O3 nanoparticles and vacancy ordering: An in situ X-ray powder diffraction study](/preview/png/1329938.png)
The formation of maghemite, γ-Fe2O3 nanoparticles has been studied by in situ X-ray powder diffraction. The maghemite was formed by thermal decomposition of an amorphous precursor compound made by reacting lauric acid, CH3(CH2)10COOH with Fe(NO3)3·9H2O. It has been shown that cubic γ-Fe2O3 was formed directly from the amorphous precursor and that vacancy ordering starts about 45 min later at 305 °C resulting in a tripled unit cell along the c-axis. The kinetics of grain growth was found to obey a power law with growth exponents n equal to 0.136(6) and 0.103(5) at 305 and 340 °C, respectively. Particles with average sizes of 12 and 13 nm were obtained in 86 and 76 min at 305 and 340 °C, respectively. The structure of cubic and vacancy ordered phases of γ-Fe2O3 was studied at 305 °C by Rietveld refinements.
Stack of powder diagrams showing the formation of γ-Fe2O3 nanoparticles and subsequent vacancy ordering at 305 °C.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 180, Issue 1, January 2007, Pages 180–185