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Composition-property-structure correlations of scandium aluminosilicate glasses revealed by multinuclear 45Sc, 27Al and 29Si solid-state NMR
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Vise andre og tillknytning
2012 (engelsk)Inngår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 95, nr 8, s. 2545-1553Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Many features of aluminosilicate glasses incorporating a rare-earth (RE) ion are dictated by its mass and cation field strength (CFS). ScAlSiO glasses are interesting because Sc3+ exhibits the highest CFS but the lowest mass of all RE3+ ions. We explore relationships between the glass composition and several physical properties, such as density, glass-transition temperature (Tg), Vickers hardness, and refractive index, over the glass forming region of the ternary Sc2O3Al2O3SiO2 system. The glasses exhibit uniform and unexpectedly low Tg-values (similar to 875 degrees C), but a high microhardness (approximate to 9.3 GPa) that correlates with the Sc2O3 content. 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy shows enhanced deshielding and a minor glass-network ordering as either the Al or Sc content of the glass increases. 27Al MAS NMR reveals that besides the expected AlO4 tetrahedra, substantial amounts of AlO5 (31%35%) and AlO6 (approximate to 5%) polyhedra are present in all ScAlSiO glass structures. 45Sc isotropic chemical shifts (similar to 92 ppm) derived from MAS and 3QMAS (triple-quantum MAS) NMR experiments are consistent with ScO6 environments.

sted, utgiver, år, opplag, sider
2012. Vol. 95, nr 8, s. 2545-1553
HSV kategori
Forskningsprogram
fysikalisk kemi
Identifikatorer
URN: urn:nbn:se:su:diva-69317DOI: 10.1111/j.1551-2916.2012.05288.xISI: 000307101000028OAI: oai:DiVA.org:su-69317DiVA, id: diva2:475951
Merknad

AuthorCount: 8;

Tilgjengelig fra: 2012-01-11 Laget: 2012-01-11 Sist oppdatert: 2017-12-08bibliografisk kontrollert
Inngår i avhandling
1. Structure-Property-Composition Correlations in Rare-Earth Alumino-silicate Glasses
Åpne denne publikasjonen i ny fane eller vindu >>Structure-Property-Composition Correlations in Rare-Earth Alumino-silicate Glasses
2012 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Rare earth (RE) alumino-silicate (AS) glasses exhibit favorable physical, mechanical and optical properties, such as high values of the glass transition temperature, Vickers hardness, and refractive index. RE2O3-Al2O3-SiO2 glasses have found several industrial applications, for example as components of optical amplifiers and lasers. Many of these features stem from the high cation field-strength (CFS) of the trivalent RE ions (proportional to the valence of the ion divided by the square of its radius), which affects not only the physical properties of the glass, but also their structures.

This thesis deals with investigations of four different RE2O3-Al2O3-SiO2 systems, where RE represents either of La, Y, Lu or Sc. The glass forming regions of the latter two were reported by us for the first time. Within each system, glasses were prepared for variable RE, Si and Al contents.

The glass structures were investigated by solid-state 29Si and 27Al nuclear magnetic resonance (NMR) spectroscopy that informs about the local Si and Al environments in the glass network, which is built from interlinked SiO4 and AlO4 groups. Higher Al coordination numbers were also revealed by 27Al NMR: their amounts were observed to increase markedly as the CFS of the RE ion increases, i.e., along the series La<Y<Lu<Sc. This thesis discusses such structure/composition relationships, as well as the correlations between the glass composition and its physical properties of density, molar volume, compactness, glass transition temperature, Vickers hardness and refractive index. Some of these properties, for example the glass transition temperature and Vickers hardness, were observed to enhance as the RE3+ CFS increased.

sted, utgiver, år, opplag, sider
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockholm University, 2012. s. 79
HSV kategori
Forskningsprogram
fysikalisk kemi
Identifikatorer
urn:nbn:se:su:diva-69325 (URN)978-91-7447-431-2 (ISBN)
Disputas
2012-02-14, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 5: Manuscript.

Tilgjengelig fra: 2012-01-23 Laget: 2012-01-11 Sist oppdatert: 2016-04-29bibliografisk kontrollert

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