Influence of selected dopands on the structure and microstructure of zinc and barium aluminates

Vrankić, Martina (2014) Influence of selected dopands on the structure and microstructure of zinc and barium aluminates. Doctoral thesis, Faculty of Science > Department of Chemistry.

Language: Croatian

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Structural studies of nanocrystalline samples of zinc aluminate (ZnAl2O4) doped with 0-11.7 at.% Mn2+, samples of ZnAl2O4 doped with 0-11.6 at.% Ti4+, samples of barium aluminate (BaAl2O4) doped with 0-8.7 at.% Eu3+ and samples of BaAl2O4 doped with 0-6.3 at.% Cr3+ have been performed in order to examine the dependence of dopand incorporation mechanism on its oxidation state and doping level. Doped ZnAl2O4 samples were prepared by the sol-gel method, while doped BaAl2O4 samples were prepared by the hydrothermal method. They were examined by X-ray powder diffraction. Crystal structures of samples were refined by the Rietveld method and their microstructure was determined simultaneously. Manganese doping of zinc aluminate caused an appearance of partial inverse spinel structure in zinc aluminate, Mn2+ occupying both tetrahedral and octahedral sites of the spinel structure. In doping, cation Ti4+ incorporated in the octahedral site of ZnAl2O4 structure solely, substituting for Al3+. In doping of BaAl2O4 cation Eu3+ substitutes for 9-coordinated Ba2+, while only a small content of Cr3+ substitutes for Al3+ in one of the available AlO4 tetrahedra, respectively. Besides the strong influence on structure of zinc aluminates and of barium aluminates, doping also influences their microstructure, because the dopand cations act as defects in the crystal structure lattice.

Item Type: Thesis (Doctoral thesis)
Keywords: doped inorganic materials, crystal structure, electron microscopy, luminescence, microstructure, X-ray diffraction
Supervisor: Gržeta, Biserka
Date: 2014
Number of Pages: 155
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Depositing User: mag. bibl. Ana Šafran
Date Deposited: 15 Oct 2014 11:16
Last Modified: 15 Jun 2015 12:23

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