ZrO_2溶胶的稳定性及溶胶-凝胶材料转变的物相-化学结构分析

Stability of ZrO_2 sol and phase-chemical structure analysis of sol-gel material transition

以Zr(NO_3)_4·5H_2O为前驱体,采用溶胶-凝胶法制备ZrO_2溶胶.通过测定ZrO_2溶胶的密度、黏度,计算ZrO_2溶胶体系的黏滞性活化吉布斯自由能,采用红外光谱、粒径分析、X射线衍射(XRD)和扫描电镜(SEM)对ZrO_2溶胶及其凝胶材料进行分析表征.结果表明,所形成的ZrO_2溶胶粒径小且分布窄,平均粒径为2.89nm.在25℃陈化的前60d内,ZrO_2溶胶的密度、黏度、粒径以及黏滞性活化吉布斯自由能略有增大,表明溶胶体系内部颗粒间有较大的摩擦力,溶胶稳定性和分散性良好.ZrO_2溶胶及其凝胶材料中均没有Zr-O键,Zr元素是以无定型ZrOC2O4·2H2O的形式存在,400℃焙烧后出现的是四方相ZrO_2晶体.

ZrO 2 sol was prepared by sol-gel method using Zr(NO 3)4·5H 2O as precursor.The Gibbs free energy of ZrO 2 sol system was calculated by measuring the density and viscosity of ZrO 2 sol.Infrared spectra(IR),particle size analysis,X-ray diffraction(XRD)and scanning electron microscopy(SEM)were used to characterize the properties of ZrO 2 sol and its gel material.The results show that the freshly prepared ZrO 2 sol has a narrow particle size distribution with an average particle size of 2.89 nm.Within the first 60 days aged at 25℃,the density,viscosity,particle size and viscosity-activated Gibbs free energy of ZrO 2 sol slightly increase,indicating that the great friction exists among the particles of the system and ZrO 2 sol has good stability and dispersibility.There is no Zr-O bond in the ZrO 2 sol and its gel material,and Zr element exists in the form of amorphous ZrOC 2O 4·2H 2O.Tetragonal ZrO 2 crystal appears in the sample calcined at 400℃.