Composition and temperature effects on minor structural species in aluminosilicate melts and glasses
Abstract/Contents
- Abstract
- In order to better understand the structure of aluminosilicate glasses and its impact on thermodynamic and transport properties, this work studies the effects of compositional and temperature variations on minor structural species in a series of aluminosilicate glasses. The presence of high-energy minor structural species such as non-bridging oxygen (NBO) and five-coordinated aluminum are not predicted by "standard" models of glass structure along the metaluminous (charge-balanced) join, where they have been observed using aluminum and oxygen nuclear magnetic resonance (NMR) spectroscopy. Two series of calcium aluminosilicate glasses were made along different silica isopleths, crossing the metaluminous join. The rate at which the five-coordinated aluminum content increases in the peraluminous region suggests that the additional aluminum is incorporated into the melt using 3-coordinated oxygen. The presence of NBO into the peraluminous region is confirmed and its value is affected by the Si/Al ratio. A similar, smaller series of potassium aluminosilicate glasses also shows the presence of NBO on the metaluminous join but at a much lower value than observed in the calcium aluminosilicate glasses. However, a series of barium aluminosilicate glasses (at a lower silica content) shows NBO content consistent with similar calcium aluminosilicate glasses; this suggests that the presence of non-stoichiometric NBO along the metaluminous join is driven by cation charge instead of cation field strength, which is confirmed to affect the amount of five-coordinated aluminum. To study the effect of temperature on these minor structural species, the glass-forming calcium aluminosilicate melts were cooled at different rates to sample the glass structure at different fictive temperatures. The five-coordinated aluminum content clearly increased with increasing fictive temperature across all samples studied, while the NBO content showed the clearest increase with increased fictive temperature in the peraluminous and high silica samples. All of these comparisons support the need for decoupled structural reactions to produce NBO and five-coordinated aluminum in these regions. Additionally, the accuracy of oxygen NMR on quantitation of structural species was tested using silicate minerals and glasses, verifying the reliability of these measurements and reaffirming that stoichiometry based methods of predicting NBO in silicate glasses remain valid.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Thompson, Linda Marie Bishop |
|---|---|
| Associated with | Stanford University, Department of Geological and Environmental Sciences. |
| Primary advisor | Stebbins, Jonathan Farwell |
| Thesis advisor | Stebbins, Jonathan Farwell |
| Thesis advisor | Bird, Dennis K |
| Thesis advisor | Brown, G. E. (Gordon E.), Jr |
| Advisor | Bird, Dennis K |
| Advisor | Brown, G. E. (Gordon E.), Jr |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Linda Marie Bishop Thompson. |
|---|---|
| Note | Submitted to the Department of Geological and Environmental Sciences. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Linda Marie Bishop Thompson
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...