Microstructure development and densification of ultrafine Y-TZP monoliths obtained by seeding-assisted chemical coprecipitation

Y-TZP seeded gel monoliths have been prepared by a sol–gel method based on the coprecipitation of Zr4+ and Y3+ precursors as hydroxides and the stabilisation of the suspension in pure ethanol with a disc turbine. The addition of solid Y-TZP nanometer-size seed particles (10 wt%) into the Y-TZP precursor solution plays a crucial role during crystallisation and densification of monoliths. Basically, it induced a preferential nucleation, which enhanced the crystallisation kinetics and the activation energy is fairly lowered As a result of the increased nucleation frequency for the crystallisation process a well-developed homogeneous porous microstructure is obtained facilitating the sintering and so the densification at lower temperatures. In this way, Y-TZP highly densified ceramic monoliths have been obtained at 1050°C, with a grain size within the nanometer range.