Publication Date:
2012-01-26
Description:
Perovskite-type LaAlO 3 nanoparticles have been prepared by a facile, rapid, and environmentally friendly molten salts method using alkali metal nitrates as low-temperature fluxes. Starting from hydrated lanthanum and aluminum nitrates and alkali metal hydroxides, the proposed methodology consists briefly of two steps: a mechanically induced metathesis reaction followed by short firing at temperatures above nitrates melting points. The purpose of the first is twofold: on the one hand to generate in situ the alkali metal nitrate flux and on the other hand, to obtain a La and Al -containing precursor material suitable for the synthesis of bulk LaAlO 3 nanoparticles in molten nitrates. Different alkali metal nitrates and eutectic mixtures were used to analyze the influence of melt basicity in the reaction outcome. Single phase LaAlO 3 was obtained directly, without any purification step when using three molten media: LiNO 3 , NaNO 3 , and their mixture; using KNO 3 as flux either alone or as part of eutectic compositions, prevents complete conversion, and the title material is obtained mixed with additional crystalline phases such as lanthanum hydroxinitrates and carbonates. As-prepared LaAlO 3 powders are composed of loosely agglomerated nanoparticles with very fine crystallite size (32–45 nm). The present method reduces considerably previously reported synthesis time/temperatures for this material.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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