Preparation of ZrO₂(3Y) encapsulated Al₂O₃ nanometer composite powders

ZrO₂(3Y) encapsulated Al₂O₃ nano composite powders were prepared by heterogeneous nucleation combined with the liquid co-deposition method using pH buffer solution as precipitator. The synthesized powders were characterized with XRD and TEM. The results indicated that the isoelectric point of Al₂O₃ suspension shifted to acidic side and the absolute value of Zeta potential also increased when a dispersant was added into the suspension. At pH 9.56, the absolute value of Zeta potential reached the maximum and the suspension was most stable. The maximum yield of the precursor was obtained at pH 9.5 and the concentration of ZrOCl₂ and YCl₃ mixed solution 0.2 mol·L^-1. There existed two phases, i.e., α-Al₂O₃ and t-ZrO₂, in the composite powders calcined at 600°C. TEM observation confirmed that nano ZrO₂(3Y) particles with a diameter of 10 nm were formed on the surface of Al₂O₃ particles.