Preparation And Quantitative Analysis Of Tetragonal Nano-ZrO₂ Powder

In this paper, ZrO2 powder prepared with sol-gel method, pressure-hydrothermal method and supercritical fluid drying (SCFD) in order to prepare from well dispersed, and the comparative anti-aging properties of the nano-ZrO2 powder for the purpose. The effects of the initial zirconium concentration, adding ammonia method and speed of precipitant, the PH value of the solution, and aging time on the ZrO2 powder agglomeration state, phase composition, particle size and powder morphology were investigated in this paper. Nano-ZrO2 powder phase composition and grain size for quantitative analysis and DTA, XRD and TEM methods such as testing the performance of heat-treated powder have been characterized.The experiments were divided into three parts. In the first part, the ZrO2 powder was made by sol-gel method. In the second part, the nano-ZrO2 powder prepared by pressure-hydrothermal method were investigated at different temperatures and pressures obtained zirconia products phase composition and grain size, to inquire the law of phase transformation and grain growth after heat treatment at different temperature and time. In the third part, after heat treatment on 550℃,the agglomeration and ageing degree of ZrO2 powder made by SCFD method using Zr(OH)4 alcogel as raw material were investigated.The results showed, under the experimental conditions, the ZrO2 made with sol-gel method by hydrogel or alcogel as a raw material was serious agglomerate. However, by using Zr(OH)4 alcogel as raw material, nano-ZrO2 powders,which were white, delicate and loose, can be made by pressure-hydrothermal method and SCFD method easily. The products using Zr(OH)4 hydrogel as raw material prepared by pressure-hydrothermal method were slightly inferior than alcogel. The result showed that by using Zr(OH)4 as raw material, the powder prepared by pressure-hydrothermal method was no fixed phrase, t-ZrO2 content was still almost 50% after 2 hours of heat treatment on 550℃and the average grain size was under 20 nm. The anti-ageing ability of nano-ZrO2 powder was comparatively well. In addition, nano-ZrO2 powder made by SCFD method was almost t-ZrO2, the average grain size was no more than 10nm, and they separated spontaneously. After 3 hours of heat treatment on 550℃, the crystalline grain grown less than 5nm.