The aim was to develop a comprehensive approach for the stabilization of aqueous dispersions for commercial zirconia particles (Tosoh TZ3Y) used in ceramics applications. Classical DLVO models allowed to describe the colloidal stability despite strong attractive forces (Hamaker constant 17kT). We investigated the volume fraction at which liquid-gel transition takes place through size distributions, rheology and small angle scattering (SAXS) experiments. This transition may originate from a broad distribution and the stability of a fraction of fines particles (< 20nm). This transition depends on the interactions : the gel appears at 20%vol for the particles when the stability of the system is controlled through ionic repulsions and at 30%vol when an additional steric barrier is promoted by adsorption of citrate. The structure of gels appears dense without heterogeneity. The impact of an addition of zirconia or silica nanoparticles to TZ3Y zirconia dispersions on the colloidal stability was also investigated both in dilute and concentrated regimes.
