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TEM Characterization of Nanostructured MgAl 2 O 4 Synthesized by a Direct Conversion Process from γ‐Al 2 O 3
Author(s) -
AlSharab Jafar F.,
Cosandey Frederic,
Singhal Amit,
Skandan Ganesh,
Bentley James
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2006.01020.x
Subject(s) - selected area diffraction , spinel , annealing (glass) , transmission electron microscopy , electron diffraction , materials science , diffraction , analytical chemistry (journal) , spectroscopy , octahedron , crystallography , energy dispersive x ray spectroscopy , scanning electron microscope , chemistry , crystal structure , nanotechnology , metallurgy , optics , physics , chromatography , quantum mechanics , composite material
Nanostructured MgAl 2 O 4 spinel was synthesized by a direct conversion process from cubic γ‐Al 2 O 3 . The effect of post‐annealing temperature (300°, 500°, and 800°C) on MgAl 2 O 4 phase formation was investigated using transmission electron microscopy, selected area electron diffraction (SAED), electron energy loss spectroscopy (EELS), and energy‐dispersive spectroscopy (EDS). Relative diffraction intensities as well as lattice parameter measurements from SAED revealed that MgAl 2 O 4 spinel structure starts forming at temperatures as low as 300°C. EELS and EDS spectrum images also revealed an increase in elemental homogeneity with increasing annealing temperature. The degree of ordering of Mg and Al between octahedral and tetrahedral sites has been determined from relative diffraction intensities. Results show that annealing to 800°C leads to a spinel phase with an order parameter of 0.78.