Study On The Preparation Of Nano-Zirconia Powders

Zirconia is applied widely in the fields refractory materials,solid fuel cell materials,catalyst carrier sensor and decorative materials due to its excellent properties of high temperature resistance,wear resistance,corrosion resistance.The particle size and dispersibility of nano-zirconia powders have a great influence on the sintering properties and even the performance of zirconium products in turn.Therefore,it is of great significance to prepare nano-zirconia powders with small particle size,high activity and excellent dispersion.After analyzing the advantages and disadvantages of the preparation method of the powders system,the nano-zirconia powders were prepared by two methods of homogeneous precipitation and hydrothermal method.Nano-zirconia powders are produced by homogeneous precipitation method.The effect and mechanism of the ratio of zirconium nitrate and urea,concentration of Zr4+,temperature of reaction,dispersant,charge control of precursor solution and other factors on the powders are studied,and the results show that:The smaller the ratio of zirconium nitrate and urea is,the more uniform the particle disperse,the greater the particle size is.When the ratio is 1:5,the nano-zirconia powders is not easy to agglomerate and has the best dispersibility and stability;with the increase of Zr4+ concentration,The powders are easy to gather.When the concentration of Zr4+is 0.15mol/L,the prepared nano-powders have good dispersibility and small particle size;the temperature of reaction has little effect on the dispersibility and particle size of nano-zirconia powders.But it has a great influence on the speed of reaction.the higher the temperature is,the faster the speed of reaction is;the nano-zirconia powders prepared with polyethylene glycol dispersant have small particle size and narrow particle size distribution,and the particle dispersion is more uniform;the dispersion of nano-zirconia powders prepared is better after the charge control technology is used in the precursor solution,and a part of cubic zirconia occurs,which result in nano-zirconia powders more stable and having better performance.Nano-zirconia powders are prepared by hydrothermal method,The influences of the ratio of zirconium nitrate and urea,the temperature of reaction and the reaction time on the particle size,dispersibility,stability and production of nano-zirconia powders are investigated.Getting the following conclusions:the dispersion and particle size of nano-zirconia powders prepared by hydrothermal method are better than the homogeneous precipitation method;the ratio of zirconium nitrate and urea has an important influence on the dispersibility of nano-zirconia powders,when the ratio is 1:4,the nano-zirconia powders have the best dispersivity,the highest production and the best stability;the dispersion of nano-zirconia powders prepared by hydrothermal method at 120? is better that at 150?,the stability of zirconia powders prepared at 120? is better than that at 150?;the longer the reaction time is,the more the production is,the better the crystallization of nano-zirconia powders is,with time going by,zirconia crystal transformation occours and nano-zirconia powders become more stable;the crystallization reaction and crystal transition of zirconia occour simultaneously in the progress of hydrothermal reaction.