The Study On The Preparation Of Zirconia Powders By Microemulsion And Partial Stabilization

Microemulsion reaction method is an effective way to prepare nano-powder,Nanoparticles prepared in this way are coated by a layer of emulsifier molecules in the surface,so it is difficulty to reunite between particles.At the same time,the reflectition is carried in the water nuclear,so that we can controll the size of particles effectively,microemulsion reaction can controll not only the size of particles but all so the morphology of particles.In this paper,selected cetyltrimethylammonium bromide as surfactant,N-butanol as surfactants to help,Cyclohexane as the oil phase to the preparation of microemulsion.We can get the former body of zirconia by the reaction between ZrOCl₂ and NH₃·H₂O,we can get the powder of zirconia after baking the former body. Using the best ratio of microemulsion,by changing the concentration of salt solution and adding get the powder with different size.So that we can Speculate the morphology of microemulsion.And then bake the powder at different temperatures, determine the relationship between the grain size and phase change with temperature. And then mix Y₂O₃ and La₂O₃ powder respectively with ZrO₂,do the heat treatment at different temperatures.Through X-ray diffraction analysis,Come to the content of the stability of ZrO₂.Compare the effect of its stability at different temperatures with different contents of Y₂O₃ and La₂O₃(3%mol and 8%mol),At the same time,analysis the effect of the adding amount to the stability.The experimental results show that:in the system of CTAB/n-butanol/ cyclohexane,when C₄H₁₀O₂ and CTAB mixed at mass ratio of 1:1,adding the 7-9ml concentration of 1mol/L solution of zirconium salt can get zirconium hydroxide with a good dispersion and a dozen nanometers in size.And after calcined at 800℃we get ZrO₂ powder with the size of about 30nm also good dispersion.Solution concentration,melting water,as well as calcination temperature effects particle size. The greater the concentration the greater the particle size;adding more solution the larger particle size;the higher the calcination temperature the larger particle size. Crystal transition takes place in the roasting process,The process of change as follows: Calcination after 400℃had the following to the amorphous state,it can be tetragonal ZrO₂ phase at 450℃,up to 800℃all tetragonal phase change into monoclinic phase of ZrO₂.At the same time,the 3mol%Y₂O₃ added zirconia has the best stability when the temperature is 1550℃,8mol%Y₂O₃ added zirconia has the best stability when temperature is 1550℃,3mol%La₂O₃ added zirconia has the best stable temperature 1450℃,8mol%La₂O₃ added zirconia for the best stable temperature 1500℃.