MAS-NMR studies of lithium aluminum silicate (LAS) glasses and glass-ceramics having different Li{sub 2}O/Al{sub 2}O{sub 3} ratio
- Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
- UCCS - Unite de Catalyse et Chimie du Solide - UMR CNRS 8181, Ecole Nationale Superieure de Chimie de Lille, Universite des Sciences et Technologies de Lille, BP 108, 59562 Villeneuve d'Ascq Cedex (France)
Emergence of phases in lithium aluminum silicate (LAS) glasses of composition (wt%) xLi{sub 2}O-71.7SiO{sub 2}-(17.7-x)Al{sub 2}O{sub 3}-4.9K{sub 2}O-3.2B{sub 2}O{sub 3}-2.5P{sub 2}O{sub 5} (5.1<=x<=12.6) upon heat treatment were studied. {sup 29}Si, {sup 27}Al, {sup 31}P and {sup 11}B MAS-NMR were employed for structural characterization of both LAS glasses and glass-ceramics. In glass samples, Al is found in tetrahedral coordination, while P exists mainly in the form of orthophosphate units. B exists as BO{sub 3} and BO{sub 4} units. {sup 27}Al NMR spectra show no change with crystallization, ruling out the presence of any Al containing phase. Contrary to X-ray diffraction studies carried out, {sup 11}B (high field 18.8 T) and {sup 29}Si NMR spectra clearly indicate the unexpected crystallization of a borosilicate phase (Li,K)BSi{sub 2}O{sub 6}, whose structure is similar to the aluminosilicate virgilite. Also, lithium disilicate (Li{sub 2}Si{sub 2}O{sub 5}), lithium metasilicate (Li{sub 2}SiO{sub 3}) and quartz (SiO{sub 2}) were identified in the {sup 29}Si NMR spectra of the glass-ceramics. {sup 31}P NMR spectra of the glass-ceramics revealed the presence of Li{sub 3}PO{sub 4} and a mixed phase (Li,K){sub 3}PO{sub 4} at low alkali concentrations. - Graphical Abstract: The {sup 11}B MAS-NMR spectra of lithium aluminum silicate (LAS) glass-ceramics indicating the formation of Li/KBSiO{sub 6} phase. This phase is isostructural with virgilite and cannot be distinguished in X-ray diffractograms.
- OSTI ID:
- 21372457
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ALUMINIUM SILICATES
BORATES
BORON COMPOUNDS
BORON SILICATES
CERAMICS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTALLIZATION
DIFFRACTION
GLASS
HEAT TREATMENTS
LITHIUM COMPOUNDS
LITHIUM OXIDES
LITHIUM PHOSPHATES
LITHIUM SILICATES
MINERALS
NMR SPECTRA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHOSPHATES
PHOSPHORUS COMPOUNDS
QUARTZ
SCATTERING
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SPECTRA
X-RAY DIFFRACTION