The effect of refluxing on the alkoxide-based sodium potassium niobate sol-gel system: Thermal and spectroscopic studies

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.12.002· OSTI ID:21504041

Chowdhury, Anirban ^[1]; Bould, Jonathan ^[1]; Londesborough, Michael G.S. ^[2]; Milne, Steven J ^[1]

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1. Institute for Materials Research, Houldsworth Building, University of Leeds, Leeds, LS2 9JT (United Kingdom)
2. Institute of Inorganic Chemistry, Academy of Science of the Czech Republic, 250 68 Rez (Czech Republic)

A study on the effects of prolonged heating under reflux conditions of up to 70 h on alkoxides of sodium, potassium and niobium dissolved in 2-methoxyethanol for the synthesis of sols of composition Na{sub 0.5}K{sub 0.5}NbO{sub 3} (NKN) has been carried out using combined thermogravimetric-Fourier transform infrared spectroscopic analyses. Extended refluxing increases the homogeneity of the Na{sub 0.5}K{sub 0.5}NbO{sub 3} (NKN) system. Spectroscopic analyses on the non-refluxed and 70 h refluxed NKN gels reveal the existence of inorganic hydrated carbonates and bicarbonates, which we propose arise from the hydration and carbonation of the samples on standing in air. The X-ray diffraction patterns of these two types of gels show orthorhombic NKN phase evolutions at higher temperatures. -- Graphical abstract: Total organic evolution plots over time for NKN dried gels obtained under different refluxing times show different thermochemical behaviours and these were investigated by thermal and spectroscopic analysis tools to find a correlation between the extent of -M-O-M- chain link formation and the amount of solvent vapour (methoxyethanol) evolution. Display Omitted Research highlights: > Prolonged refluxing of sol-gel NKN precursor solutions improves final properties of an NKN system. > An NKN process thermo-chemistry with thermal and spectroscopic analysis tools was explored. > An FTIR of NKN gels reveals tendency of NKN systems for rehydration and recarbonation on standing.

• OSTI ID: 21504041
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 2; Other Information: DOI: 10.1016/j.jssc.2010.12.002; PII: S0022-4596(10)00540-2; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACID CARBONATES
ALKOXIDES
CARBONATES
HEATING
HYDRATION
INFRARED SPECTRA
NIOBATES
ORTHORHOMBIC LATTICES
POTASSIUM COMPOUNDS
SODIUM COMPOUNDS
SOL-GEL PROCESS
SOLVENTS
SPECTROSCOPY
SYNTHESIS
THERMAL GRAVIMETRIC ANALYSIS
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
CARBON COMPOUNDS
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
GRAVIMETRIC ANALYSIS
NIOBIUM COMPOUNDS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
REFRACTORY METAL COMPOUNDS
SCATTERING
SOLVATION
SPECTRA
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS