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Densification and crystallization of lead titanate aerogels

: Löbmann, P.; Glaubitt, W.; Fricke, J.

Journal of the American Ceramic Society 80 (1997), No.10, pp.2658-2666
ISSN: 0002-7820
Journal Article
Fraunhofer ISC ()
Aerogel; Kristallisierung; lead titanate aerogel; Sol-Gel-Prozeß; Verdichtung

Crack-free monolithic lead titanate (PbTiO3, or PT) aerogels were prepared via a sol-gel process and dreying in supercritical carbon dioxide. The material was characterized by thermogravimetric analysis, dilatometry, helium pycnometry, and X-ray diffraction. Skeletal densification was the main reason for the observed shrinkage of the heat-treated porous material st temperatures < 450 deg C. The transition (at temperatures of 500 - 600 deg C) from an amorphous state to the crystalline (tetragonal) PT was accompanied by significant particle coarsening, as revealed by transmission electron microscopy. Nitrogen adsorption measurements confirmed that crystallization was preceded by the formation of interparticle necks.