Sol-emulsion-gel synthesis of shaped powders in the system BaO-TiO2

Citation
M. Chatterjee et al., Sol-emulsion-gel synthesis of shaped powders in the system BaO-TiO2, J SOL-GEL S, 16(1-2), 1999, pp. 143-149
Citations number
22
Categorie Soggetti
Material Science & Engineering
Journal title
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
ISSN journal
09280707 → ACNP
Volume
16
Issue
1-2
Year of publication
1999
Pages
143 - 149
Database
ISI
SICI code
0928-0707(199910)16:1-2<143:SSOSPI>2.0.ZU;2-G
Abstract
Shaped tetragonal barium titanate (BaTiO3) particles were prepared by the s ol-emulsion-gel method with systematic variation of the concentration of a non-ionic surfactant in the organic phase ("oil phase") of water-in-oil (w/ o) emulsions above or below the critical micelle concentration (CMC). An ac etate-based sol with equivalent oxide ratio BaO : TiO2 = 1 : 1 was selected for the study. Micelle formation of the surfactant and their self-aggregat ion apparently played an important role in controlling the shape and size o f the droplets and accordingly shape and size of the final barium titanate particles resulting therefrom. Transmission electron microscopy (TEM) revea led that with low concentration of the surfactant (2-5 vol%) ill-formed sph eres were obtained. Spherical particles were formed with increasing the sur factant concentration to 7 vol%. At 12 vol% of the surfactant, rod-like par ticles were first found to form, which with further increase in surfactant concentration to 15-20 vol%, gradually transformed to cube-like/lamellar ty pe particles. Attempts have been made to explain the various particle shape s in terms of surfactant aggregation.