Aerogel partially densified

Beurroies I, Bourret D, Sempere R et al (1995) Gas-Permeabihty of Partially Densified Aerogels. Journal of Non-Crystalline Solids 186 328-333... [Pg.498]

Anglaret E., Beurroies I., Duffours L., Levelut C, Foret M., Delord P, Woignio- T, Phalippou J., Pelous J. A low frequency Raman study of fractons in partially densified silica aerogels. J. Non-Cryst. Solids 1998 225 248-253... [Pg.797]

Partially densified silica aerogels have also been characterized by SAXS and, despite the fact that this method does not allow to directly determine pore size, the results obtained are compatible with the disappearance of pores of decreasing size as the pressure increases (Dieudonne, 1998). [Pg.901]

Quantitatively establishing the relation between the size of the pores that are compressed and the pressure of densification is obviously essential in order to determine pore volume distribution as a function of pore size. This relation has been established by Pirard et al. (Pirard, 1995) from the analysis of nitrogen adsorption-desorption isotherms of aerogels that were partially densified by mercury porosimetry at increasing pressures. Two types of aerogels were analyzed silica-zirconia aerogels, whose densification is completely... [Pg.901]

Figure 5-11. SAXS measurements obtained for a series of fractal partially densified aerogels. The sintering treatment is performed at 1000° C as a function of time. decreases while a increases (see arrows). The slope (fractal dimension) is drawn as guides for eyes.

$Figure 5-11. SAXS measurements obtained for a series of fractal partially densified aerogels. The sintering treatment is performed at 1000° C as a function of time. decreases while a increases (see arrows). The slope (fractal dimension) is drawn as guides for eyes.$

The densification of aerogels under isostatic mercury pressure can be totally irreversible after pressurization-depressurization, as is the case for silica-zirconia aerogels (Pirard, 1995). But most of the time there is a partial reversibihty, which can be relatively important if the sample is maintained at moderate pressure for a short time (Alaoui, 1998). Anyway, the sample volume is smaller after densification, even after a possible relaxation. Therefore, it is possible to study the effect of isostatic pressure on aerogels by characterizing the texture of materials first densified to a known value of isostatic pressure. [Pg.900]

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