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Abstract

Mixed oxides of zirconium and yttrium [ZrO.sub.2 (Y.sub.2 O.sub.3)], with an yttrium content (as computed as elemental metal) comprised within the range of from about 15 to about 21% by weight, as spherical particles with size comprised within the range of from 0.1 to 2 .mu.m, with an average size of the particles lower than 1 .mu.m, in the cubic crystal form, are obtained by: preparing a mixture by starting from an aqueous solution of zirconium and yttrium carboxylates; an organic solvent selected from the group consisting of nitriles or alcohols; and a non-ionic surfactant; causing solid colloidal particles of the precursor of mixed zirconium/yttrium oxides to precipitate from said mixture, by operating at a pH value comprised within the range of from 5 to 7, at room temperature or at temperature close to room temperature; and calcining said precipitate of solid particles at a high temperature to cause said solid particles to be directly converted from the amorphous state into the cubic crystal form. According to a particular form of practical embodiment, ultrasounds are applied to the mixture during said precipitation step, to further reduce the size of the precipitated particles. The so obtained mixed oxides of zirconium and yttrium are suitable for use in the electronic sector, in particular as a solid electrolyte for fuel flow cells.

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