Study On Preparation Technique Of High-dispersion Nano-zirconia

Nano-zirconia has extremely excellent physical and chemical properties, so it is widely used in preparation of structural and functional materials, especially as a source of high-performance ceramic materials. However, Nano-zirconia powders easily agglomerate together which hindered its application, because that nano-powders have a huge surface area and surface energy. Thereby, it is necessary to increase the dispersion of nano-powders.This paper mainly study on the synthesis of Nano-zirconia with hydrothermal method. Firstly, The precursor which was heat-treated by hydrothermal was prepared by Stirring semi-batch reactor (SSBR), and the crystallinity and dispersibility caused from the addition of different kinds of minneralizer,change of concentration^ hydrothermal temperature and time during the hydrothermal-process were investigated. Secondly, the precursor was prepared by Process intensification equipment—Rotor-Stator Reactor (RSR) on the basis of above, and then was heat-treated by the optimum conditions. The conclusions got from this study were as follows:1,The crystallinity and dispersibility increases with the addition of mineralizer. When the Tri-ethanolamine (TEA) was used as mineralizer and the concentration was 0.1mol/L, the well-dispersed nano-zirconia powders with narrow size distribution(15-20nm) was synthesized at 220℃for 6 hours by hydrothermal method.2,The morphology and phase of nano-zirconia are different with different kinds of minaeralizer and the change of its concentration. When the Tri-ethanolamine (TEA) was used as mineralizer, the nano-zirconia particles are respectively spherical and square-shaped at 0.lmol/L and 0.5mol/L. When the sodium hydroxide was used as mineralizer, the phase of nano-zirconia is changing regularly with the increasing of concentration. The phase is tetragonal at 0.1mol/L, the monoclinic is increasing and tetragonal is reducing between 0.1mol/L and 0.5mol/L, the monoclinic content is maximum at 2mol/L, However, the phase returns to pure tetragonal when the concentration increased to 4mol/L.3,The dispersibility of nano-zirconia which was prepared by rotor-stator reactor(RSR) is a little better compare to which was prepared by Stirring semi-batch reactor (SSBR), and the size of particles is also smaller and more homogeneous, the average size is about 12nm and size distribution is 10-15nm.