Study On The Preparation Of Monodispersed Zirconia Nano Powder And Its Property

Homogeneous and well-crystallized nano- ZrO₂(Y₂O₃) powders were prepared by complex coprecipitation using a complex compound of H₂O₂. The precipitate Zr(OH)_4-x(OOH)_x was prepared by ligands of–OH and–OOH derived from H₂O₂, using ZrOCl₂ and Y₂O₃ as raw materials and NH4OH as a precipitant. The effects of raw materials and precipitant concentration, temperature, aging time and drying ways on the particle size, aggregation state, flowability and sintering activity, were investigated in this paper. The optimum process conditions for the manufacture of zirconia precursor powders were determined after considering the effects above. TG-DTA, XRD, TEM, nitrogen adsorption and some other experiment methods have been used to characterize the products. In addition, the sintering behavior and the mechanical property of the zirconia powders prepared by different drying methods were also studied. The research results show:1. Ultrafine zirconia powders, with particle size in the range 30～40 nm, can be prepared by calcining at 800℃for 1 hour. The zirconium peroxide was obtained under the condition of reaction pH value 8, ZrOCl2 concentration 0.6mol/L and aging time 70min. The optimum mol ratio of H2O2 and Zr⁴⁺ was 1:12. The differences of precipitation pH value for Zr⁴⁺ and Y³⁺ could be reduced after adding hydrogen peroxide because of the complex formed. The uniformity of component distribution of Y₂O₃ and ZrO₂ was improved by adding appropriate hydrogen peroxide according to the result measured by EDX3. It was favorable for the filterability of the precipitate, which would lead to a short preparation period. The morphology of synthesized particles was relatively spherical and uniform4. The microwave drying way could not only shorten drying time but also reduce aggregation intensity of nano-ZrO₂ powders. Since the direction of thermal transmission was identical to that of the mass transfer during microwave drying process, the internal pressure gradient formed in this drying process made water to diffuse to the surface of particles fast, leading to great decrease of drying time5. Compared with oven drying method, the nano-ZrO₂ powders prepared by microwave drying method have low aggregation intensity and high sintering...