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Characterisation of Nanocrystalline Magnesium Oxide by X‐Ray Absorption Spectroscopy
Author(s) -
Savin Shelley L. P.,
Chadwick Alan V.,
O'Dell Luke A.,
Smith Mark E.
Publication year - 2007
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600750
Subject(s) - nanocrystalline material , materials science , grain size , calcination , x ray absorption spectroscopy , amorphous solid , microstructure , magnesium , oxide , chemical engineering , ball mill , particle size , absorption spectroscopy , analytical chemistry (journal) , mineralogy , metallurgy , nanotechnology , crystallography , chemistry , optics , organic chemistry , physics , engineering , catalysis
There are numerous methods of preparing nanocrystalline materials. Magnesium oxide is an ideal model system on which to probe the relation of the preparative route and the microstructure. Using X‐ray absorption spectroscopy (XAS) we show that the sol‐gel route can be used to prepare highly crystalline material provided there is careful control of the calcination conditions. In the present work this is achieved by calcining at high temperatures (at least 800 °C). However, this results in grain growth that can be prevented by the addition of a pinning agent, SiO 2 , during the preparation of the sol. The pinned samples maintain a particle size of 11 nm even after calcining at 1000 °C. Ball‐milling is a common method of preparing nanocrystalline oxides, however the present work shows that this produces a significant fraction of amorphous material, the fraction increasing with decreasing grain size ( e.g. ≈30 % for a grain size of 23 nm).