Details
| Original language | English |
|---|---|
| Article number | 119454 |
| Journal | Journal of non-crystalline solids |
| Volume | 519 |
| Early online date | 24 May 2019 |
| Publication status | Published - 1 Sept 2019 |
Abstract
To understand the impact of dissolved water on structure and properties, four boron-rich glasses of molar compositions 15-x Na2O x CaO 15 SiO2 70 B2O3 (with x = 0, 7.5, 10)and 10 Na2O 15 SiO2 75 B2O3 were prepared and subsequently hydrated (up to 8 wt% H2O). Density measurements show a non-linear trend upon hydration implying large structural changes in particular at water contents <2 wt%. Near-infrared spectroscopy shows hydroxyl groups are the dominant species in all glasses upon the entire range of water content. Molecular H2O is detectable only at total water contents >2 wt%. 11B MAS NMR spectra show that the abundance of BO4 species is mainly controlled by ratio of (Na2O + CaO)/B2O3 while incorporation of water plays a minor role. Compared to borate glasses, the efficiency of formation of BO4 tetrahedra is favored by crosslinking of the network by SiO4-units. The glass transition temperatures, determined by differential thermal analysis, decreases continuously with water content due to breakage of B-O-B bonds by hydrolysis. However, compared to silicates and aluminosilicates, the effect of dissolved water is less pronounced which can be explained by weaker B-O-B bonds in comparison to Si-O-Si bonds.
Keywords
- High pressure, Infrared spectroscopy, NMR spectroscopy, Silicoborate glasses, Water speciation
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Materials Science(all)
- Ceramics and Composites
- Physics and Astronomy(all)
- Condensed Matter Physics
- Materials Science(all)
- Materials Chemistry
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In: Journal of non-crystalline solids, Vol. 519, 119454, 01.09.2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The influence of H2O and SiO2 on the structure of silicoborate glasses
AU - Balzer, Robert
AU - Behrens, Harald
AU - Schuth, Stephan
AU - Waurischk, Tina
AU - Reinsch, Stefan
AU - Müller, Ralf
AU - Fechtelkord, Michael
AU - Deubener, Joachim
N1 - Funding Information: This research was supported by the German Science Foundation (DFG) within the priority program SPP1594 (Founding number: BE 1720/31-2 ). The author thanks three anonymous reviewers for their constructive comments, which helped to improve the quality of this paper.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - To understand the impact of dissolved water on structure and properties, four boron-rich glasses of molar compositions 15-x Na2O x CaO 15 SiO2 70 B2O3 (with x = 0, 7.5, 10)and 10 Na2O 15 SiO2 75 B2O3 were prepared and subsequently hydrated (up to 8 wt% H2O). Density measurements show a non-linear trend upon hydration implying large structural changes in particular at water contents <2 wt%. Near-infrared spectroscopy shows hydroxyl groups are the dominant species in all glasses upon the entire range of water content. Molecular H2O is detectable only at total water contents >2 wt%. 11B MAS NMR spectra show that the abundance of BO4 species is mainly controlled by ratio of (Na2O + CaO)/B2O3 while incorporation of water plays a minor role. Compared to borate glasses, the efficiency of formation of BO4 tetrahedra is favored by crosslinking of the network by SiO4-units. The glass transition temperatures, determined by differential thermal analysis, decreases continuously with water content due to breakage of B-O-B bonds by hydrolysis. However, compared to silicates and aluminosilicates, the effect of dissolved water is less pronounced which can be explained by weaker B-O-B bonds in comparison to Si-O-Si bonds.
AB - To understand the impact of dissolved water on structure and properties, four boron-rich glasses of molar compositions 15-x Na2O x CaO 15 SiO2 70 B2O3 (with x = 0, 7.5, 10)and 10 Na2O 15 SiO2 75 B2O3 were prepared and subsequently hydrated (up to 8 wt% H2O). Density measurements show a non-linear trend upon hydration implying large structural changes in particular at water contents <2 wt%. Near-infrared spectroscopy shows hydroxyl groups are the dominant species in all glasses upon the entire range of water content. Molecular H2O is detectable only at total water contents >2 wt%. 11B MAS NMR spectra show that the abundance of BO4 species is mainly controlled by ratio of (Na2O + CaO)/B2O3 while incorporation of water plays a minor role. Compared to borate glasses, the efficiency of formation of BO4 tetrahedra is favored by crosslinking of the network by SiO4-units. The glass transition temperatures, determined by differential thermal analysis, decreases continuously with water content due to breakage of B-O-B bonds by hydrolysis. However, compared to silicates and aluminosilicates, the effect of dissolved water is less pronounced which can be explained by weaker B-O-B bonds in comparison to Si-O-Si bonds.
KW - High pressure
KW - Infrared spectroscopy
KW - NMR spectroscopy
KW - Silicoborate glasses
KW - Water speciation
UR - http://www.scopus.com/inward/record.url?scp=85066062060&partnerID=8YFLogxK
U2 - 10.1016/j.jnoncrysol.2019.05.030
DO - 10.1016/j.jnoncrysol.2019.05.030
M3 - Article
AN - SCOPUS:85066062060
VL - 519
JO - Journal of non-crystalline solids
JF - Journal of non-crystalline solids
SN - 0022-3093
M1 - 119454
ER -