Coesite Formation at Ambient Pressure and Low Temperatures
Partial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of ∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS m...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2008-01-01
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| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2008/406067 |
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| author | J. R. Martínez A. Vázquez-Durán G. Martínez-Castañón G. Ortega-Zarzosa S. A. Palomares-Sánchez Facundo Ruiz |
| author_facet | J. R. Martínez A. Vázquez-Durán G. Martínez-Castañón G. Ortega-Zarzosa S. A. Palomares-Sánchez Facundo Ruiz |
| author_sort | J. R. Martínez |
| collection | DOAJ |
| description | Partial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of ∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that partial crystallization of the glass matrix in the form of coestite was obtained at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The presence of coesite is corroborated by the Rietveld refinement method. |
| format | Article |
| id | doaj-art-ae10f2d678ba4246a81fd05e2d75365e |
| institution | OA Journals |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2008-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-ae10f2d678ba4246a81fd05e2d75365e2025-08-20T02:23:28ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422008-01-01200810.1155/2008/406067406067Coesite Formation at Ambient Pressure and Low TemperaturesJ. R. Martínez0A. Vázquez-Durán1G. Martínez-Castañón2G. Ortega-Zarzosa3S. A. Palomares-Sánchez4Facundo Ruiz5Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, MexicoCentro de Investigación en Óptica, A.C., 37150 León, Gto., MexicoFacultad de Estomatología, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, MexicoFacultad de Ciencias, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, MexicoFacultad de Ciencias, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, MexicoFacultad de Ciencias, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, MexicoPartial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of ∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that partial crystallization of the glass matrix in the form of coestite was obtained at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The presence of coesite is corroborated by the Rietveld refinement method.http://dx.doi.org/10.1155/2008/406067 |
| spellingShingle | J. R. Martínez A. Vázquez-Durán G. Martínez-Castañón G. Ortega-Zarzosa S. A. Palomares-Sánchez Facundo Ruiz Coesite Formation at Ambient Pressure and Low Temperatures Advances in Materials Science and Engineering |
| title | Coesite Formation at Ambient Pressure and Low Temperatures |
| title_full | Coesite Formation at Ambient Pressure and Low Temperatures |
| title_fullStr | Coesite Formation at Ambient Pressure and Low Temperatures |
| title_full_unstemmed | Coesite Formation at Ambient Pressure and Low Temperatures |
| title_short | Coesite Formation at Ambient Pressure and Low Temperatures |
| title_sort | coesite formation at ambient pressure and low temperatures |
| url | http://dx.doi.org/10.1155/2008/406067 |
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