Hydrothermal synthesis of zirconia nanomaterials

Yttria-stabilised zirconia powders and films have been obtained from Zr(IV) peroxides by hydrothermal crystallisation at temperatures in the range 125-200 degreesC. The thermodynamic evaluation evidenced that formation of Zr(OH)(5)(-) in H2O2 solutions increases solubility of Zr (IV) hydrated species and improves the kinetics of the new phase formation by the solubilisation-reprecipitation process. Powders with crystallite sizes in the range 6-22 nm have been obtained. The kinetic parameters for the crystallisation process were calculated using Avrami's approach to control the nanocrystalline structure. Nanocrystalline films consisting of platelet YSZ crystallites were also hydrothermal deposited on alumina substrate of YSZ suggesting a layer to layer growing mechanism. (C) 2001 Elsevier Science Ltd. All rights reserved.