Phase separation in the H2O-SiO2 system
Phase separation in the H2O-SiO2 system is examined in view of immiscibility in the alkali and alkaline earth silicates, critical parameters of which correlate with the charge and size of network modifier cations. Although the miscibility gaps of the H2O-SiO2 system have not been completely characte...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-06-01
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| Series: | Journal of Non-Crystalline Solids: X |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590159123000146 |
| _version_ | 1797798637902757888 |
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| author | Vincent J. McGahay |
| author_facet | Vincent J. McGahay |
| author_sort | Vincent J. McGahay |
| collection | DOAJ |
| description | Phase separation in the H2O-SiO2 system is examined in view of immiscibility in the alkali and alkaline earth silicates, critical parameters of which correlate with the charge and size of network modifier cations. Although the miscibility gaps of the H2O-SiO2 system have not been completely characterized, available data indicate a phase separation tendency greater than that of Li2O-SiO2, consistent with H+ being smaller than Li+. Extension of critical parameter correlations to H2O-SiO2 leads, however, to unrealistic predictions of critical composition due to neglect of cation/anion size asymmetry. To capture this effect, a new coulombic cell model is developed and combined with an asymmetric hard-sphere mixture model. The resulting equation of state predicts H2O-SiO2 critical parameters consistent with expected critical temperature and observed critical concentration. Suppression of the miscibility gap with pressure is explained as a consequence of silanol condensing into molecular H2O and increasing the background dielectric constant. |
| first_indexed | 2024-03-13T04:07:53Z |
| format | Article |
| id | doaj.art-eef01cba76904801884c200938a4340b |
| institution | Directory Open Access Journal |
| issn | 2590-1591 |
| language | English |
| last_indexed | 2024-03-13T04:07:53Z |
| publishDate | 2023-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Non-Crystalline Solids: X |
| spelling | doaj.art-eef01cba76904801884c200938a4340b2023-06-21T06:59:48ZengElsevierJournal of Non-Crystalline Solids: X2590-15912023-06-0118100162Phase separation in the H2O-SiO2 systemVincent J. McGahay0GLOBALFOUNDRIES, Inc., 2070 Route 52, Hopewell Jct, NY, 12533, USAPhase separation in the H2O-SiO2 system is examined in view of immiscibility in the alkali and alkaline earth silicates, critical parameters of which correlate with the charge and size of network modifier cations. Although the miscibility gaps of the H2O-SiO2 system have not been completely characterized, available data indicate a phase separation tendency greater than that of Li2O-SiO2, consistent with H+ being smaller than Li+. Extension of critical parameter correlations to H2O-SiO2 leads, however, to unrealistic predictions of critical composition due to neglect of cation/anion size asymmetry. To capture this effect, a new coulombic cell model is developed and combined with an asymmetric hard-sphere mixture model. The resulting equation of state predicts H2O-SiO2 critical parameters consistent with expected critical temperature and observed critical concentration. Suppression of the miscibility gap with pressure is explained as a consequence of silanol condensing into molecular H2O and increasing the background dielectric constant.http://www.sciencedirect.com/science/article/pii/S2590159123000146Silica glassWaterPhase separationEquation of stateCoulombic interactionHard sphere mixtures |
| spellingShingle | Vincent J. McGahay Phase separation in the H2O-SiO2 system Journal of Non-Crystalline Solids: X Silica glass Water Phase separation Equation of state Coulombic interaction Hard sphere mixtures |
| title | Phase separation in the H2O-SiO2 system |
| title_full | Phase separation in the H2O-SiO2 system |
| title_fullStr | Phase separation in the H2O-SiO2 system |
| title_full_unstemmed | Phase separation in the H2O-SiO2 system |
| title_short | Phase separation in the H2O-SiO2 system |
| title_sort | phase separation in the h2o sio2 system |
| topic | Silica glass Water Phase separation Equation of state Coulombic interaction Hard sphere mixtures |
| url | http://www.sciencedirect.com/science/article/pii/S2590159123000146 |
| work_keys_str_mv | AT vincentjmcgahay phaseseparationintheh2osio2system |