TEM Characterization of Nanostructured MgAI2O4 Synthesized by a Direct Conversion Process from (gamma)-A12O3

Nanostructured MgA12O4 spinel was synthesized by a direct conversion process from cubic ... The effect of post-annealing temperature ... on MgA12O4 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 MgA12O4 spinel structure starts forming at temperatures as low as ... 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 ... leads to a spinel phase with an order parameter of 0.78. [PUBLICATION ABSTRACT]