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- Title
Synchrotron X-ray powder diffraction and extended X-ray absorption fine structure spectroscopy studies on nanocrystalline ZrO<sub>2</sub>-CaO solid solutions.
- Authors
Fábregas, Ismael Oscar; Lamas, Diego Germán; De Reca, Noemí Elizabeth Walsöe; Fantini, Márcia C. A.; Craievich, Aldo F.; Prado, Rogério Junqueira
- Abstract
The crystal structure and the local atomic order of a series of nanocrystalline ZrO2-CaO solid solutions with varying CaO content were studied by synchrotron radiation X-ray powder diffraction and extended X-ray absorption fine structure (EXAFS) spectroscopy. These samples were synthesized by a pH-controlled nitrate-glycine gel-combustion process. For CaO contents up to 8 mol%, the t' form of the tetragonal phase (c/a > 1) was identified, whereas for 10 and 12 mol% CaO, the t" form (c/a = 1; oxygen anions displaced from their ideal positions in the cubic phase) was detected. Finally, the cubic phase was observed for solid solutions with CaO content of 14 mol% CaO or higher. The t'/t" and t"/cubic compositional boundaries were determined to be at 9 (1) and 13 (1)mol% CaO, respectively. The EXAFS study demonstrated that this transition is related to a tetragonal-to-cubic symmetry change of the first oxygen coordination shell around the Zr atoms.
- Subjects
SYNCHROTRON radiation; X-ray diffraction; EXTENDED X-ray absorption fine structure; NANOCRYSTALS; SOLID solutions
- Publication
Journal of Applied Crystallography, 2008, Vol 41, Issue 4, p680
- ISSN
0021-8898
- Publication type
Article
- DOI
10.1107/S0021889808013046