Monolithic crystalline lead zirconate titanate aerogels

• Published in: Journal of non-crystalline solids 1998-04, Vol.225 (1-3), p.130-134
• Main Authors: Löbmann, Peer, Glaubitt, Walther, Geis, Stefan, Fricke, Jochen
• Format: Article
• Language: English
• Subjects: Alkogels; Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Polycrystalline PZT; Xerogels
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/S0022-3093(98)00108-2

Stoichiometric lead zirconate titanate (PbZr 0.53Ti 0.47O 3, PZT) alkogels were prepared by a sol–gel technique. Drying under ambient conditions yielded xerogels while solvent exchange and supercritical drying either in carbon dioxide or isopropanol led to highly porous aerogels. A porosity of only 3% can be detected in the amorphous air-dried xerogels. Gels supercritically dried in carbon dioxide are also amorphous and exhibit a surface area of 323 m 2 g −1 as determined by nitrogen adsorption and a porosity of 84%. Neither xerogels nor CO 2-dried aerogels can be transformed into polycrystalline PZT by heat treatment without cracking. Aerogels dried in supercritical isopropanol exhibit porosities comparable to samples dried in carbon dioxide. XRD and DTA measurements indicate that during drying, metallic lead is formed as an intermediate phase. This type of aerogel can be transformed into polycrystalline PZT with porosities exceeding 70%. These results are compared to previous studies of lead titanate (PT) aerogels. Even though the final porosity of PZT aerogels is smaller than that of the corresponding PT aerogels, their enhanced mechanical stability may prove useful for piezoelectric materials with low acoustic impedances.