水热法合成条件对氧化锆晶相影响的光谱研究

Influence of the Crystal Phase of Nano-ZrO_2 Prepared by Hydrothermal Method

以硝酸锆为前驱物,用水热法分别合成了纯单斜相、四方相以及四方和单斜混合相的氧化锆纳米粒子。应用XRD、拉曼光谱和TEM探讨了水热过程中前驱体浓度、晶化温度和晶化时间对ZrO2晶粒尺寸和相变的影响。结果表明,水热制备过程中上述合成条件均影响ZrO2晶粒尺寸,其中晶化温度对其影响最大,但是晶化温度对ZrO2的形貌影响不大。延长晶化时间有利于单斜晶相的形成,而且随着晶化时间延长,ZrO2的晶化程度增加。在水热合成过程中采用较低的前驱体浓度、较高晶化温度及延长晶化时间有利于控制合成单斜相ZrO2。

Pure monoclinic ZrO2, tetragonal ZrO2 and the mixed phases of monoclinic and tetragonal ZrO2, were prepared by hydrothermal method using Zr（NO3 ）4 as precursor. The influences of the precursor concentration, crystallization temperature, and crystallization time on the particle size and crystalline phase of ZrO2 nanoparticles were studied by XRD, Raman spectroscopy and TEM. It is found that all the above synthesis conditions have influences on the particle size of ZrO2. Among those above experimental conditions, the particle size of ZrO2 is more related to the crystallization temperature while the crystallization temperature has little influence on the morphology of ZrO2. Furthermore, it is show that the monoclinic ZrO2 is easily formed for the longer crystallization time, and the crystallization degree of ZrO2 is increased when longer crystallization time is used. This paper provides a strategy to synthesize the monoclinic ZrO2 using low precursor concentration, high crystallization temperature and the long crystallization time.