Microstructural characterization of mechanically activated ZnO–Cr2O3 system

An equimolar mixtures of starting ZnO and Cr2O3 powders were mechanically activated by grinding using a planetary ball mill for various periods of time (40--320min). Formation of nanocrystalline ZnCr2O4 as normal spinel structure at room temperature is detected in all samples--after ball--milling. A detailed XRD structural analysis (the relative phase abundances of different phases, lattice parameter changes, site occupancy, the average primary crystallite sizes, crystal lattice microstrains) is realized by the pattern decomposition technique, performed in accordance with the procedure based on Rietveld software KOALARIET--XFIT. Due to the importance of cation distribution on the chemical and physical properties of spinels, a study of site occupation factors of ZnCr2O4 spinels has been undertaken. The calculation based on the atomistic methods for the description of the perfect and defect spinel ZnCr2O4 crystal lattice is applied and the presence of the individual structural defects is determined.