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Metastable phase diagram of nanocrystalline `ZrO IND.2´ `Sc IND.2´`O IND.2´solid solutions

Paula M Abdala Aldo Felix Craievich; Márcia Carvalho de Abreu Fantini; Márcia Laudelina Arruda Temperini; Diego G Lamas

Journal of Physical Chemistry v. 113, n. 43, p, 18661-18666, 2009

Washington, DC 2009

Acesso online

  • Título:
    Metastable phase diagram of nanocrystalline `ZrO IND.2´ `Sc IND.2´`O IND.2´solid solutions
  • Autor: Paula M Abdala
  • Aldo Felix Craievich; Márcia Carvalho de Abreu Fantini; Márcia Laudelina Arruda Temperini; Diego G Lamas
  • Assuntos: FÍSICO-QUÍMICA; SOLUÇÕES
  • É parte de: Journal of Physical Chemistry v. 113, n. 43, p, 18661-18666, 2009
  • Descrição: We have investigated the crystal structures and phase transitions of nanocrystalline ZrO2-1 to -13 mol % Sc2O3 by synchrotron X-ray powder diffraction and Raman spectroscopy. ZrO2-Sc2O3 nanopowders were synthesized by using a stoichiometric nitrate-lysine gel-combustion route. Calcination processes at 650 and at 850 °C yielded nanocrystalline materials with average crystallite sizes of (10 ( 1) and (25 ( 2) nm, respectively. Only metastable tetragonal forms and the cubic phase were identified, whereas the stable monoclinic and rhombohedral phases were not detected in the compositional range analyzed in this work. Differently from the results of investigations reported in the literature for ZrO2-Sc2O3 materials with large crystallite sizes, this study demonstrates that, if the crystallite sizes are small enough (in the nanometric range), the metastable t′′-form of the tetragonal phase is retained. We have also determined the t′-t′′ and t′′-cubic compositional boundaries at room temperature and analyzed these transitions at high temperature. Finally, using these results, we built up a metastable phase diagram for nanocrystalline compositionally homogeneous ZrO2-Sc2O3 solid solutions that strongly differs from that previously determined from compositionally homogeneous ZrO2-Sc2O3 solid solutions with much larger crystallite sizes
  • Editor: Washington, DC
  • Data de criação/publicação: 2009
  • Formato: p. 18661-18666.
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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