Structure Analysis of Nanocrystalline MgO Aerogel Prepared by Sol-Gel Method
| Autor: | Roman Pielaszek, Grzegorz Dercz, Janusz J. Malinowski, Krystian Prusik, L. Pająk, Wojciech Pudło |
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| Rok vydání: | 2007 |
| Předmět: |
Materials science
Rietveld refinement Magnesium Analytical chemistry chemistry.chemical_element Aerogel Condensed Matter Physics Atomic and Molecular Physics and Optics Nanocrystalline material law.invention Crystallography chemistry law Specific surface area General Materials Science Calcination Particle size Crystallite |
| Zdroj: | Solid State Phenomena. 130:203-206 |
| ISSN: | 1662-9779 |
| Popis: | Wet gel obtained by sol-gel technique was dried in supercritical CO2 to prepare hydrated form of magnesium oxide. Calcination at 723 K under vacuum yielded nanocrystalline MgO aerogel. Structure studies were performed by X-ray diffraction, scanning and transmission electron microcopies. Electron microscopy images reveal rough, unfolded and ramified structure of solid skeleton. Specific surface area SBET was equal to 238 m2/g. X-ray pattern reveals the broadened diffraction lines of periclase, the only crystalline form of magnesium oxide. The gamma crystallite size distribution was determined using FW 5 4 / 5 1 M method proposed by R. Pielaszek. The obtained values of and σ (measure of polydispersity) of particle size parameters are equal to 6.5 nm and 1.8 nm, respectively, whereas the average crystallite size estimated by Williamson-Hall procedure was equal to 6.0 nm. The obtained at Rietveld refinement Rwp, and S fitting parameters equal to 6.62% and 1.77, respectively, seem to be satisfactory due to the nanosize of MgO crystallites and because of the presence of amorphous phase. |
| Databáze: | OpenAIRE |
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