Synthesis of lanthanum aluminate by thermal decomposition of hydrated nitrates

Kumar, M. Dharmendira; Srinivasan, Thilagavathy; Subramanian, C.; Ramasamy, P.

doi:10.1016/s0272-8842(96)00050-8

Cited by 7 publications

(1 citation statement)

References 9 publications

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“…1b where the XRD patterns shown belong to an equimolar mixture of both nitrates fired for 3 h at 350 and 600°C: i.e., both XRD patterns are characteristic of a mostly amorphous material with no sign of reaction which is in agreement with the existing literature reports. Hence, attempts to synthesize lanthanum orthoaluminate by first melting and then dehydrating and firing equimolar mixtures of La(NO 3 ) 3 Á6H 2 O and Al(NO 3 ) 3 Á9H 2 O have shown the onset of crystallinity of the perovskite-type phase taking place typically in the 700-1000°C range [26,28,29]; even more, the asprepared samples still contained a large fraction of amorphous material and needed of further heating at temperatures higher than 1100°C to achieve complete conversion and avoid the formation of the very stable corundum phase. Having this in mind, the aim of introducing a metathesis reaction before firing in the attempt to synthesize LaAlO 3 from the corresponding hydrated metal nitrates, fulfills two goals: on the one hand to generate in situ sodium nitrate, high-lattice energy byproduct and thus the driving force behind the displacement reaction itself, and at the same time, the flux for the second step, that is the MSS; on the other hand and equally important, to circumvent La 3?…”

Section: Synthesis Of Pure Laalo 3 Powdersmentioning

confidence: 99%

Molten salts synthesis and electrical properties of Sr- and/or Mg-doped perovskite-type LaAlO3 powders

et al. 2012

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Lanthanum-based LaBO 3 oxides adopting the very stable perovskite structure are currently considered attractive materials for a growing number of applications in the field of solid-state ionics. In particular, LaAlO 3 -based perovskites are promising electrolyte materials for solid oxide fuel cells because they show almost pure oxygen ion conductivity at low oxygen partial pressures and high temperatures as well as excellent thermal and chemical stability under the standard operating conditions. This article describes a low-temperature synthesis of pure and acceptordoped perovskite-type LaAlO 3 nanopowders via a facile and environmental-friendly molten salts method. Using hydrated metal nitrates and sodium hydroxide as raw materials, the proposed methodology consists of two steps: a mechanically induced metathesis reaction and short firing above NaNO 3 's melting point. The purpose of the first is twofold: i.e., to generate in situ the NaNO 3 flux and to obtain a suitable precursor for the synthesis of the target materials in molten nitrates. Accordingly, pure and Mg-and/or Sr-doped LaAlO 3 powders were obtained directly without using any purification step at temperatures B500°C. When preparing the Mg-containing samples, NaNO 2 was also added to the reaction mixture to increase melt reactivity. The formation of the target series in the molten salt is thought to proceed through a ''dissolution-precipitation'' mechanism with LaAlO 3 particles precipitating during cooling from a solution oversaturated with reactants. Electrical properties of the as-prepared materials were measured as a function of temperature and frequency by means of impedance spectroscopy and found comparable to those shown by similar materials prepared using more complicated routes.

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Section: Synthesis Of Pure Laalo 3 Powdersmentioning

confidence: 99%

Molten salts synthesis and electrical properties of Sr- and/or Mg-doped perovskite-type LaAlO3 powders

et al. 2012

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Atomic Layer Deposition and Properties of Lanthanum Oxide and Lanthanum‐Aluminum Oxide Films

Kukli

Ritala

Pore

et al. 2006

Chemical Vapor Deposition

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Atomic layer deposition (ALD) of lanthanum oxide on glass and silicon substrates was examined using lanthanum silylamide, La[N(SiMe 3 ) 2 ] 3 , and water as precursors in the substrate temperature range of 150-250°C. The effect of pulse times and precursor evaporation temperature on the growth rate and refractive index was investigated. The films remained amorphous regardless of the deposition conditions. The resulting La 2 O 3 films contained noticeable amounts of hydrogen and silicon and were chemically unstable while stored in ambient air. Lanthanum aluminum oxide films were achieved with stoichiometry close to that of LaAlO 3 at 225°C from La[N(SiMe 3 ) 2 ] 3 , Al(CH 3 ) 3 , and H 2 O. The lanthanum b-diketonate precursor, La(thd) 3 , was used as the reference precursor.

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Low-temperature synthesis, luminescence and phonon properties of Er and/or Dy doped LaAlO3 nanopowders

Mączka

Mendoza‐Mendoza²,

Fuentes³

et al. 2012

Journal of Solid State Chemistry

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Synthesis of lanthanum aluminate by thermal decomposition of hydrated nitrates

Cited by 7 publications

References 9 publications

Molten salts synthesis and electrical properties of Sr- and/or Mg-doped perovskite-type LaAlO3 powders

Molten salts synthesis and electrical properties of Sr- and/or Mg-doped perovskite-type LaAlO3 powders

Atomic Layer Deposition and Properties of Lanthanum Oxide and Lanthanum‐Aluminum Oxide Films

Low-temperature synthesis, luminescence and phonon properties of Er and/or Dy doped LaAlO3 nanopowders

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