Structure of nanoporous zirconia-based powders synthesized by different gel-combustion routes

CASANOVA, J. R; FÁBREGAS, I.O.; LAMAS, D.G.; LASCALEA, G.E; WALSOE DE RECA, N.E.; CRAIEVICH A.F.; SANTILLI, C.V.

Activity Report of the Brazilian Synchrotron Light Laboratory

Año: 2006 p. 743 - 744

   Zirconia-based ceramics that retain their metastable tetragonal phase at room temperature are widely studied due to their excellent mechanical and electrical properties. Since submicrometric grain sizes are required to retain this phase in dense ceramic bodies, these materials are prepared from precursor nanopowders with high specific surface areas. Particularly the gel-combustion synthesis method has attracted great interest due to its simple procedure and low cost. The method is based on the gelling and subsequent combustion of an aqueous solution containing salts of the desired metals (usually nitrates) and an organic fuel (glycine, citric acid, urea). The violent reaction produces a large volume of gases that promotes the disintegration of the precursor gel yielding very small grains. The as-reacted ashes are then calcined in order to eliminate the organic residuals.In this work, the morphology of nanoporous ZrO2-2.8 mol% Y2O3 powders synthesized by different gel-combustion routes was investigated by small-angle X-ray scattering (SAXS). Other techniques, such as X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM) and BET specific surface area measurements, were also employed.