Nanostructured alumina from freeze-dried precursors

Nanostructured alumina from freeze-dried precursors

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Nanostructured alumina from freeze-dried precursors

Show simple item record Villanueva Ibáñez, Regina Gómez, Andrés Burguete Llorens, Pedro Luis Martínez, Eduardo Beltrán Porter, Aurelio Sapiña Navarro, Fernando Vicent, Mónica Sánchez, Enrique 2014-12-16T14:45:23Z 2014-12-16T14:45:23Z 2011
dc.description.abstract Nanocrystalline alumina has been obtained on the 100-g scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous solutions of different aluminium-containing products,namely aluminium acetate and aluminium L-lactate. Samples prepared at different temperatures (from 873 to 1573 K in steps of 100 K) were characterized by X-ray powder diffraction, scanning and transmission electron microscopy, and surface area measurements. In the acetate case, the transformation sequence involves the formation of q-Al2O3 as an intermediate phase between g- and a-Al2O3, whereas this q phase is not observed in the lactate case. TEM and SEM images show the nanoparticulate character of the aluminas obtained at relatively low temperatures, with typical particle size in the 5 to 10 nm range. Progressive grain growth occurs as temperature increases. Otherwise, the precursor characteristics have a clear influence on the microstructure of the resulting aluminas , as reflected also by the measured BET surface area values. Whereas long aluminium acetate fibres results in open arrays of low aggregated alumina particles, large aluminium lactate sheets lead to comparatively compact alumina microstructures. Nanostructured alumina obtained from the lactate precursor has been to reconstituted in a granulated powder with sufficient consistence and flowability to allow it to be thermal sprayed and deposited on a stainless steel substrate. X-ray powder diffraction data show that g-Al2O3 is the major phase in the coating, which includes also a-Al2O3 particles. SEM results offer evidences on the nanostructured character of the coating.
dc.relation.ispartof Journal of the American Ceramic Society, 2011, vol. 94, num. 1, p. 236-243
dc.rights.uri info:eu-repo/semantics/openAccess
dc.source Villanueva Ibáñez, Regina; Gómez, Andrés; Burguete, Pedro; Martínez, Eduardo; Beltrán, Aurelio; Sapiña, Fernando; Vicent, Mónica; Sánchez, Enrique (2011) Nanostructured alumina from freeze-dried precursors Journal of the American Ceramic Society 94 1 236 243
dc.subject Ceràmica
dc.title Nanostructured alumina from freeze-dried precursors
dc.type info:eu-repo/semantics/article 2014-12-16T14:45:23Z
dc.identifier.idgrec 064504

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