• Citer

Influence of synthesis conditions on microstructure and phase transformations of annealed Sr 2 FeMoO 6−x nanopowders formed by the citrate–gel method

par Yarmolich, Marta;Kalanda, Nikolai;Demyanov, Sergey;Terryn, Herman ;Ustarroz Troyano, Jon ;Silibin, Maksim;Gorokh, Gennadii
Référence Beilstein J. Nanotechnol, 7, page (1202-1207)
Publication Publié, 2016

Article révisé par les pairs

• Accès en ligne
• Détails
• Contenu
• Statistiques

Résumé :

The sequence of phase transformations during Sr 2 FeMoO 6−x crystallization by the citrate–gel method was studied for powders syn-thesized with initial reagent solutions with pH values of 4, 6 and 9. Scanning electron microscopy revealed that the as-produced and annealed powders had the largest Sr 2 FeMoO 6−x agglomerates with diameters in the range of 0.7–1.2 µm. The average grain size of the powders in the dispersion grows from 250 to 550 nm with increasing pH value. The X-ray diffraction analysis of the powders annealed at different temperatures between 770 and 1270 K showed that the composition of the initially formed Sr 2 FeMoO 6−x changes and the molybdenum content increases with further heating. This leads to a change in the Sr 2 FeMoO 6−x crystal lattice pa-rameters and a contraction of the cell volume. An optimized synthesis procedure based on an initial solution of pH 4 allowed a single-phase Sr 2 FeMoO 6−x compound to be obtained with a grain size in the range of 50–120 nm and a superstructural ordering of iron and molybdenum cations of 88%.