Abstract

RODRIGUEZ-PAEZ, J. E; MAFLA, A; ANDRADE, G  and  LATORRE, G. OBTENCION DE SOLES ESTABLES DE SILICE - TITANIA UTILIZANDO COMO ACOMPLEJANTE ACETILACETONATO. Rev. LatinAm. Met. Mat. [online]. 2002, vol.22, n.1, pp.16-20. ISSN 0255-6952.

Sol-gel processing has become a well established techniqhe for producing ceramic powders or glasses. The future of this technology however depends on whether it will be able to make better materials or even completely new products. This processing has been utilized to synthesize several interesting systems, e.g. the SiO2 - TiO2 system. SiO2 - TiO2 glasses have also been prepared by the sol-gel process. These glasses show very low termal expansion and high refractive index. On the other hand, SiO₂ - TiO₂ coatings can be deposited on metals to improve their resistance to oxidation and corrosion or to modify their surface properties. The big problem in the stable multicomponent geles is that the hydrolysis and condensation velocities are diferent for each precursor, TEOS and Ti(OBu)₄ in this work. The chemical control of these reactions is currently perfomed dy adding complexing reagents that react with metal alkoxides at a molecualr level, giving rise to new molecular precursors of different structure, reactivity and functionanality. This paper shows that stable TEOS - Ti(OBu)₄ - H₂O sold can be reproducibly prepared in the presence of acetylacetone. We shall then show that the acac behaves as a ligand, directly bonded to the titanium ion. This the formation of precipitate and gelation is promoted. Infra-red spectroscopy and viscosity measures were used to demostrated this behaviour of the system.

Keywords : Sol-gel; silicon-titanium; acetylacetone.