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|title: ||Enhanced BaZrO3 mechanosynthesis by the use of metastable ZrO2 precursors|
|authors: ||Sherafat, Z.|
Frade, J. R.
Paydar, M. H.
Mather, G. C.
Fagg, D. P.
|keywords: ||DOPED BARIUM ZIRCONATE|
|issue date: ||2014|
|publisher: ||ROYAL SOC CHEMISTRY|
|abstract: ||The current work assesses the impact of structural differences between stable and metastable ZrO2 precursors on the mechanochemical preparation of BaZrO3. Monoclinic (m-ZrO2) and tetragonal (t-ZrO2) zirconia polymorphs were prepared without stabilizing additives by slow alkaline precipitation. High-energy milling of the individual ZrO2 precursors induced different partial transformations in each case. The as-synthesized m-ZrO2 powders showed partial conversion to the tetragonal polymorph on mechanical activation, reaching about 10% t-ZrO2 after 420 min accompanied by increases in strain. In contrast, the as synthesized t-ZrO2 powders underwent the inverse transformation to the monoclinic phase, producing about 50% m-ZrO2 after 120 min with the liberation of strain. The t-ZrO2 precursor was shown to exhibit the higher reactivity with barium peroxide, yielding significantly earlier formation of barium zirconate under room-temperature mechanosynthesis. The progress of the mechanochemical formation of BaZrO3 has been discussed with respect to the differing behaviour of the ZrO2 precursors upon mechanical activation and associated thermodynamic perspectives.|
|publisher version/DOI: ||http://doi.org/10.1039/c4dt00683f|
|source: ||DALTON TRANSACTIONS|
|appears in collections||CICECO - Artigos|
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