Structure of heat-treated sol-gel SiO2 glasses containing silver

Garnica-Romo, Ma. Guadalupe; González‐Hernández, J.; Hernández-Landaverde, M. A.; Vorobiev, Yu. V.; Ruíz, Facundo; Martı́nez, J. R.

doi:10.1557/jmr.2001.0275

Cited by 32 publications

(24 citation statements)

References 26 publications

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“…1 and 2, a more pronounced effect in the case of the samples A was observed. This crystallization process can be understood in accordance with the previous report [9,10,11] in two important aspects, a) it is the structure of the SiO 2 matrix which is determined by the relation H 2 O/TEOS in the starting solution. b) Due to diffusion process of the Ag atoms in the growth and nucleation of Ag colloidal particles.…”

Section: Discussion Resultssupporting

confidence: 84%

“…In the same way recently our research group has reported the crystallization of SiO 2 sol-gel made with the introduction of the metal nitrates in the starting solution, Ag, Cu and mixtures of Ag and Cu [9,10,11,12] obtaining low temperatures of crystallization, 600 ºC for quartz in the mixture with AgNO 3 and (Cu(NO 3 ) 2 ) and 500 ºC for the α-cristobalite with the introduction of AgNO 3 .…”

Section: Introductionmentioning

confidence: 54%

“…of Ag, to the cristobalite phase was found. In a similar work [9,10,11,30] sol-gel glasses with the introduction of Ag and Cu particles by nitrates the transformation of the SiO 2 matrix to quartz and cristobalite phase at temperature annealing of 600 ºC [10] and 800 ºC was observed [29].…”

Section: Discussion Resultsmentioning

confidence: 83%

“…Previous work of our group observed two necessary conditions for the transformation of the SiO 2 amorphous network to cristobalite phase [9,10,11]. First there is the conformation structure of the SiO 2 similar to the cristobalite phase which is obtained with higher ratios of H 2 O/TEOS and the growing of colloidal Ag particles.…”

Section: Discussion Resultsmentioning

confidence: 87%

“…For example with Ag nitrates in sol-gel glasses [9,10,11,30] or with the introduction of Ag in melting glasses. Structural changes in the SiO 2 matrix can be induced with the introduction of several kinds of particles, metallic and metallic oxides, such as Cu, Ag, Au [2,9,10,11], or in mixtures of SiO 2 with metallic oxides (MgCO 3 , CaCO 3 , Li 2 CO 3 ,SrO, ZnO) and thermal annealing [8]. In sol-gel glasses with Ag introduction by nitrates in the starting solution and with a H 2 O/TEOS ratio of 11.7 a crystallization process of the SiO 2 at annealing temperatures of 500 ºC with 4 %vol.…”

Section: Discussion Resultsmentioning

confidence: 99%

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Evolución estructural del sistema SiO2-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Romo¹,

Torres²,

Flores³

et al. 2011

Bol. Soc. Esp. Ceram. Vidr.

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Structural evolution of Sol-Gel glasses in powder form and coatings with incorporation of Ag particles at the starting solution showed an evolution from SiO 2 amorphous matrix to the cristobalite phase with the annealing treatment at around 800 ºC for one hour. This structural evolution was obtained at lower Ag concentration up 0.7 %vol. Two series of samples were studied, A) series using HNO 3 and B) series using HCl as catalytic agent; in both series grenetine was used as a dispersing agent to avoid the precipitation of Ag particles. We found the incorporation of silver in the xerogeles matrix promotes the devitrification process at relatively low temperatures with the presence of partial crystallization in form of cistobalite. This structure was produced by controlling the catalytic agent quoted in the preparation process. The EPR and UV-Vis absorption spectra show the presence of Fe 3+ ions as a contaminant in the source of the Ag particles, due to the process to obtain these particles. By means the IR spectra a high (OH -) concentration at higher temperatures was observed in this system, until 600 ºC at difference of the sol-gel glasses made with incorporation of Ag particles by nitrates. The color evolution of the coating samples with the annealing temperature varies from a light brown at 100 ºC to yellow at 500 ºC. Keywords: sol-gel, Ag particles, cristobaliteEvolución estructural del sistema SiO 2 -Ag preparado por el proceso Sol-gel con incorporación de partículas de Ag.La evolución estructural de vidrios de Sol-Gel en forma de polvos y recubrimientos preparados con la incorporación de partículas de Ag a partir de la solución precursora muestra la evolución de la matriz amorfa de SiO 2 a la fase cristobalita utilizando tratamientos térmicos alrededor de 800 °C por un tiempo de una hora. Dicha evolución estructural fue obtenida en concentraciones bajas a partir de 0.7% de Ag. Dos series de muestras fueron estudiadas, la serie A) usando HNO 3 y la serie B) usando HCl como agente catalítico; en ambas series se uso grenetina como agente dispersante para evitar la precipitación de las partículas de Ag. Nosotros encontramos que la incorporación de plata en la matriz de los xerogeles promueve el proceso de desvitrificación a temperaturas relativamente bajas con la presencia de una cristalización parcial en forma de cristobalita. Esta estructura fue producida controlando el agente catalítico mencionado en el proceso de preparación. Los espectros de EPR y absorción UV-Vis muestran la presencia de iones Fe 3+ como un contaminante proveniente de las partículas de Ag, debido al proceso en el que fueron obtenidas las partículas. Por medio de espectroscopía IR se observo que en el sistema hay una alta concentración de (OH -) a temperaturas altas, hasta 600 ºC a diferencia de los vidrios producidos por sol-gel con la incorporación de partículas de Ag en forma de nitratos. La evolución del color en muestras con el recubrimiento con el tratamiento térmico varía de café ligero a 100 ºC hasta amarillo a 500 ºC.

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Section: Discussion Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 54%

Section: Discussion Resultsmentioning

confidence: 83%

Section: Discussion Resultsmentioning

confidence: 87%

Section: Discussion Resultsmentioning

confidence: 99%

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Evolución estructural del sistema SiO2-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Romo¹,

Torres²,

Flores³

et al. 2011

Bol. Soc. Esp. Ceram. Vidr.

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Crystallization of Amorphous SiO₂ Microtubes Catalyzed by Lithium

Zhao

Langner

et al. 2007

Adv Funct Materials

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Amorphous silica formed by thermally oxidizing silicon is commonly eligible for lithographic patterning or can be grown on patterned substrates. However, it is still a challenge to combine controlled microstructuring with controlled crystallization of SiO2. Here, it is shown that traces of volatile lithium species transported through the gas phase catalyze the crystallization of silica integrated into common silicon microstructures. The selected crystallization temperature determines which polymorph forms. As an example, the formation of quartz, tridymite, and cristobalite microtubes by thermally oxidizing macroporous silicon is investigated. Lithium‐induced crystallization may extend state‐of‐the‐art silicon technology and yield nano‐ and microstructures consisting of different silica polymorphs, which are, in contrast to many functional oxides, nontoxic.

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Formation of Ag‐Cu nanoparticles in SiO₂ films by sol‐gel process and their effect on the film properties

Flores

Garnica-Romo

González‐Hernández

et al. 2007

Phys. Status Solidi (c)

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Sol-gel thin films and microcrystalline powders of SiO 2 doped with Ag and Cu were obtained under environmental conditions of pressure and temperature. The precursor material was a mixture of water, tetraethyl-orthosilicate, ethanol and aqueous solutions of Ag and Cu salts, the components were taken in ratios known to provide SiO 2 matrix material with good structure. The annealing was performed in oxidizing and reducing atmosphere, the temperature varied in the range of 100 -800 °C. Formation of metal particles of 100 nm order of magnitude was confirmed by X-ray, optical and SEM analysis. In presence of metal particles, the SiO 2 matrix was crystallized in α-cristobalite at annealing temperature as low as 500 °C, and in quartz form at 800 °C. A simple model treating the metal-induced low-temperature crystallization is presented. The material obtained is promising for the use as optical filter, gas sensing element and antibacterial agent.

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Structure of heat-treated sol-gel SiO₂ glasses containing silver

Cited by 32 publications

References 26 publications

Evolución estructural del sistema SiO<sub>2</sub>-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Evolución estructural del sistema SiO<sub>2</sub>-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Crystallization of Amorphous SiO₂ Microtubes Catalyzed by Lithium

Formation of Ag‐Cu nanoparticles in SiO₂ films by sol‐gel process and their effect on the film properties

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Structure of heat-treated sol-gel SiO2 glasses containing silver

Cited by 32 publications

References 26 publications

Evolución estructural del sistema SiO<sub>2</sub>-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Evolución estructural del sistema SiO<sub>2</sub>-Ag preparado por el proceso Sol-Gel con incorporación de partículas de Ag

Crystallization of Amorphous SiO2 Microtubes Catalyzed by Lithium

Formation of Ag‐Cu nanoparticles in SiO2 films by sol‐gel process and their effect on the film properties

Contact Info

Product

Resources

About

Structure of heat-treated sol-gel SiO₂ glasses containing silver

Crystallization of Amorphous SiO₂ Microtubes Catalyzed by Lithium

Formation of Ag‐Cu nanoparticles in SiO₂ films by sol‐gel process and their effect on the film properties