Preparation Of Zirconia Nano Powder And Stability Studies

Stability zirconia nano-materials have exhibited promising applications in optoelectronic devices,gas sensors,refractory materials,catalysts,and many other fields because of their unique properties as low thermal conductivity,high chemical stability,surface acidity,oxidizing and reducing.However,due to the limitations of the preparation and aging treatment methods,it cause particle aggregation serious,poor dispersion,instabilities and uncontrollable problem,limiting its application in many high-techs industry.The main research contents and results of this study are mainly as follow:In the paper,zirconia nano powder were prepared by hydrothermal hydrolysis process.The effect of hydrothermal time,pH,temperature and organic additive glycerol on the particle size,crystalline and stability of the zirconia powder were investigated experimentally and carries on the quantitative analysis,fitting out the test data.The preparation samples of nano zirconia powder under different hydrothermal conditions were characterized by using XRD and SEM analysis technology.Results the crystallinity rises with the increase of the hydrothermal temperature.With the increase of the hydrothermal temperature from 150 ℃ to 250 ℃,the particle diameter increases first,and then decreasesbecause nucleation rate increases rapidly;the pH values of the reaction solution influence the crystallinity of sample.Selecting a suitable pH value can reduce reunion between powder particles and improve the dispersion of powder.The average partical size of the samples increases with reaction progress.Zirconia powder doped with 3% Y and Glycerol prepared at 200 ℃,pH=10,t=12h and then calcining them at 1000℃ for 12 h,has good dispersion,narrow particle size distribution,and a single cubic phase.Conclusion,the samples of nano stable zirconia powde of controllable particle size were prepared by setting the hydrothermal hydrolysis conditions,and Yttrium doped effectively improve the stability of zirconia.The addition of glycerol could improve evidently the stability and dispersion of zirconia powder,calcination stabilized zirconia nano powder could effectively reduce partical size distribution and improve the crystalline.The preparation samples of Zr1-xYxO₂-0.5x（x=0,0.03,0.05,0.07,0.10,0.13）doped with different proportion were study Y³⁺doping ratio and calcination temperature on the influence of YSZ crystal structure and grain size by using XRD and SEM analysis technology.The results show that: doping Y³⁺ ratio less than 3mol% YSZ power are pure monoclinic and tetragonal crystal structure,YSZ power is pure cubic crystal structure by rising to 5mol%¹3mol;Crystal structure of YSZ powder affects its grain size,C-ZrO₂ powder grain size is larger than other crystal structure;When Y³⁺ ratio was below 10mol%,part of C-ZrO₂ and t-ZrO₂ was transformed to m-ZrO₂ as calcination temperature increased.With the increase of doped proportion,transformation ratio decrease,when Y³⁺ ratio was 10mol%¹3mol%,ZrO₂ crystal structure kept stable as calcination temperature increased at 1200℃,average crystal size grew from 14.6 nm to 33 nm and good dispersion.Ce_xY_0.05Zr_0.95-xO_1.97（x=0、0.03、0.06、0.09、0.12、0.15）powder were prepared by hydrothermal,the results show that the preparation sample of Ce_xY_0.05Zr_0.95-xO_1.97（x=0、0.03、0.06、0.09、0.12、0.15）powder are nano-scale powder,good dispersion,the grain size in the range of about 10 nm.Oxygen ion vacancies introduced by Y³⁺ and Ce4+ ion modify the crystal structure of pure zirconia with the cubic phase structure of zirconia stabilized to room temperature.The lattice parameters slightly increases and the diffraction peak of sample shift to small angle with increasing Ce content;The sample of Ce_xY_0.05Zr_0.95-xO_1.97（x=0、0.03、0.09、0.15）calcined aging treatment were described via XRD、SEM.The results indicate that the crystal of the sample of Ce_xY_0.05Zr_0.95-xO_1.97 calcined aging treatment in 800 ℃¹200 ℃transform to the tetragonal and the monoclinic phase when the dope is less than 9%;The cubic crystal structure of the samples of Ce_xY_0.05Zr_0.95-xO_1.97 calcined aging treatment in 800 ℃¹000 ℃ transform to the tetragonal when the dope is more than 9% and the diameter of particle can be controlled by calcination temperature,The samples of powder calcined in 1200 ℃ are pure the tetragonal,good dispersion,crystal size about 100 nm.