Microporous Substructure of Porous Glasses: Dynamic and Equilibrium Approaches

Крейсберг, В. А.; Rakcheev, V. P.; Антропова, Т. В.

doi:10.1007/s10934-005-5228-x

Cited by 12 publications

(7 citation statements)

References 22 publications

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“…Figure 3 illustrates the microporous substructure at distinct levels of magnification. It gives a qualitative impression of the pore morphology and supports the results of a more quantitative study [6], which stated a multimodal size distribution. It compares favorably with the electron micrographs taken from the surface morphology in [10,11].…”

Section: Proceedings Of the Topical Meeting Of The European Ceramic Ssupporting

confidence: 83%

“…The porous sample exhibiting average pore diameters of 5 nm (for details, cf. [6]) was produced from the initial bulk glass of the composition 8Na 2 O · 22B 2 O 3 · 70SiO 2 (mol %) by acid leaching of the chemically unstable phase components of the phase-separated sodium boro-…”

Section: Sample Preparation and Experimental Techniquementioning

confidence: 99%

“…Consequently, the SiO 2 content of the nanoporous glass was enriched. The multimodal size distribution of pores was analyzed in detail in [6].…”

Section: Proceedings Of the Topical Meeting Of The European Ceramic Smentioning

confidence: 99%

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Mechanical properties and structure of a nanoporous sodium borosilicate glass

et al. 2007

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The nanohardness ( H ) and microhardness ( H M ) of sodium borosilicate glasses with and without nanopores were studied. From nanoindentation measurements, along with the hardness H , the Young's modulus E was derived. While both H and H M varied between ~10 GPa and ~7 GPa for the bulk glass, the values for nanoporous specimens were one order of magnitude lower at about 0.5 GPa. The Young's moduli were found to be ~82 GPa and ~5 GPa for bulk and porous glasses, respectively. Cracks and pileups were observed, respectively, arising from microindents and nanoindents in the bulk glass, whereas none of them could be detected in the nanoporous material. The molecular structures of both glasses studied by X-ray diffraction are similar.

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Section: Proceedings Of the Topical Meeting Of The European Ceramic Ssupporting

confidence: 83%

Section: Sample Preparation and Experimental Techniquementioning

confidence: 99%

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Mechanical properties and structure of a nanoporous sodium borosilicate glass

et al. 2007

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“…In our recent studies [14][15][16], we proposed using both the equilibrium and kinetic desorption isotherms (the method of diffusion diagnostics) in order to examine porous glasses containing micropores and mesopores simultaneously. The high sensitivity of the mass spectrometric analysis in this method makes it possible to measure micropores with small volumes in the presence of mesopores.…”

Section: Influence Of the Acid Concentration On The Morphology Of Micmentioning

confidence: 99%

“…In our previous works [14][15][16], these methods were applied to investigate the influence of the composition of the initial alkali borosilicate glasses and the conditions used for their phase separation on the structure of porous glasses. It was found that porous glasses have not only a through mesoporous substructure but also a polymodal microporous substructure.…”

Section: Investigation Techniquesmentioning

confidence: 99%

Influence of the acid concentration on the morphology of micropores and mesopores in porous glasses

2006

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The polymodal microporosity and mesoporosity of porous glasses prepared by through leaching of phase-separated alkali borosilicate glasses in hydrochloric acid solutions of different concentrations are investigated by two new methods based on an analysis of the kinetic and equilibrium isotherms of gas desorption at a temperature of 77.5 K under low partial pressures, as well as by a modified classical adsorption method under medium and high pressures. It is established that an increase in the concentration of hydrochloric acid in the leaching solution brings about transformations in the microporous and mesoporous structures of the porous glasses. The structural transformations can be summarized as follows: (i) a considerable decrease in the specific surface of mesopores and the corresponding increase in the diameter of secondary silica globules, (ii) a decrease in the mesopore volume and the corresponding increase in the coordination number of the packing of secondary silica globules in channels formed upon phase separation, (iii) an increase in the diameter of mesopores arising from gaps between secondary silica globules in channels formed upon phase separation, (iv) an increase in the diameter of regions in these channels that are partially or completely free from secondary silica globules, and (v) the formation of ultramicropores with a molecular size of 0.4-0.5 nm.

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