TY - JOUR
T1 - Microstructure characterization and phase transformation kinetics of ball-mill prepared nanocrystalline Mg-Zn-ferrite by Rietveld's analysis and electron microscopy
AU - Dutta, H.
AU - Sinha, M.
AU - Lee, Y. C.
AU - Pradhan, S. K.
PY - 2007/9/15
Y1 - 2007/9/15
N2 - Nanocrystalline Mg-Zn-ferrite is prepared by ball milling the stoichiometric powder mixture of MgO, ZnO and α-Fe2O3. Reduction of particle size and collision temperature favors formation of non-stoichiometric ferrite phase. The process of mechanosynthesis of Mg-Zn-ferrite leads to the formation of a metastable inverse spinel structure at the early stage of milling. In the course of milling up to 25 h leads to inverse spinel transform to its normal counterpart. Structural and microstructural evaluation of the unmilled and ball-milled samples have been characterized by Rietveld's method of structure refinement of X-ray powder diffraction data and confirmed by direct observations using FE-SEM and HR-TEM. Particle size, RMS lattice strain, change in lattice parameters and phase content of individual phases have been estimated from Rietveld's analysis. A comparative study of microstructure revealed from direct observations corroborates the findings of X-ray diffraction study in all respects. Analysis of ball-milled samples reveals that the inverse spinel phase content started to reduce in relatively long milling time and disappeared completely within 20 h milling time. After 25 h of milling, ball-milled powder mixture contain normal phase of Mg-Zn-ferrite with a trace amount of α-Fe2O3.
AB - Nanocrystalline Mg-Zn-ferrite is prepared by ball milling the stoichiometric powder mixture of MgO, ZnO and α-Fe2O3. Reduction of particle size and collision temperature favors formation of non-stoichiometric ferrite phase. The process of mechanosynthesis of Mg-Zn-ferrite leads to the formation of a metastable inverse spinel structure at the early stage of milling. In the course of milling up to 25 h leads to inverse spinel transform to its normal counterpart. Structural and microstructural evaluation of the unmilled and ball-milled samples have been characterized by Rietveld's method of structure refinement of X-ray powder diffraction data and confirmed by direct observations using FE-SEM and HR-TEM. Particle size, RMS lattice strain, change in lattice parameters and phase content of individual phases have been estimated from Rietveld's analysis. A comparative study of microstructure revealed from direct observations corroborates the findings of X-ray diffraction study in all respects. Analysis of ball-milled samples reveals that the inverse spinel phase content started to reduce in relatively long milling time and disappeared completely within 20 h milling time. After 25 h of milling, ball-milled powder mixture contain normal phase of Mg-Zn-ferrite with a trace amount of α-Fe2O3.
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U2 - 10.1016/j.matchemphys.2007.04.019
DO - 10.1016/j.matchemphys.2007.04.019
M3 - Article
AN - SCOPUS:34547676681
SN - 0254-0584
VL - 105
SP - 31
EP - 37
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 1
ER -