Preparation of ZrO_2(3Y)encapsulated Al_2O_ 3 nanometer composite powders

ZrO_2(3Y)encapsulated Al_2O_3 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 Al_2O_3 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 ZrOCl_ 2and YCl_ 3mixed solution 0.2 mol·L~ -1.There existed two phases,i.e.,α-Al_2O_3 and t-ZrO_2,in the composite powders calcined at 600℃.TEM observation confirmed that nano ZrO_2(3Y)particles with a diameter of 10 nm were formed on the surface of Al_2O_3 particles.