水热合成硅酸锌纳米粉体及其形成机理的研究

Formation Mechanism of Zn_2SiO_4 Nano Powder Synthesized by Hydrothermal Method

以醋酸锌为锌源、正硅酸乙酯为硅源水热合成硅酸锌(Zn2SiO4)晶体。研究了反应时间、温度、pH以及不同的反应溶剂对Zn2SiO4晶体生长的影响。采用X射线衍射仪(XRD)分析样品物相,扫描电镜(SEM)和透射电镜(TEM)对样品晶粒聚集成球的过程在结构和形貌上进行表征。利用Johnson-Mehl-Avrami(JMA)方程对Zn2SiO4晶体进行生长动力学分析。结果表明:随着温度升高与反应时间的延长,球状Zn2SiO4不断长大,结晶性能逐渐增强。水热合成的Zn2SiO4晶体Avrami指数n145℃=0.55、n165℃=0.60、n205℃=0.71、n185℃=0.85,表明晶体的形成有从扩散机制向成核机制转变的趋势。

The Zn2SiO4 crystal wre synthesized by hydrothermal method,using zinc acetate as zinc source and TEOS（ tetraethoxysilane） as silicon sources. The influence of reaction time,temperature,p H and different reaction solvent on the growth of Zn2SiO4 crystal were studied. The phase,the structure and morphology were characterized by X-ray diffraction（ XRD）,scanning electron microscope（ SEM） and transmission electron microscope（ TEM）. The growth kinetics of Zn2SiO4crystal was investigated through the calculation of JMA equation. The results show that globular Zn2SiO4 becomes greater in size and crystallization properties of Zn2SiO4 get enchanced with the elevation of temperature and the extention of reaction time. The Avrami exponent of Zn2SiO4was n145℃= 0. 55,n165℃= 0. 60,n205℃= 0. 71,n185℃= 0.85. It reveals the formation of crystals have a trend from diffusion mechanism to the nucleation mechanism.