(中山大学物理系,广州510275)
摘 要: 采川惰性气体保护蒸发凝聚技术,制备了粒径为4~15nm的稀土金属Gd微粉。利用小角X射线散射(SAXS)、X射线衍射曲线宽化(XRD)、喇曼散射光谱(RSS)及电子显微镜(TED)对所制备的纳米Gd微粉(nm-Gd)进行了较广泛和深入的微观分析,探讨了nm-Gd微粉的粒径分布及其结构特征。nm-Gd体系的平均粒径d与制备气压P符合如下线性关系:d = a + blnP。粒径分布函数符合Rayleigh统计分布,这不同于一般文献中采用TEM方法分析得出的对数正态分布。此外还对nm-Gd体系的比表而积、表而原子百分比及界面体积分数等结构参数进行了评估,以揭示它们与平均粒径d的关系。实验结果与理论计算曲线能较好吻合。
关键字: 稀土元素 纳米材料 微观分析
OF NANOMETER GADOLINIUM POWDERS
(Department of Physics,Zhongshan University,Guangzhou 510275)
Abstract:Nanometer-size gadolinium powders (nm-Gd) have been prepared by means of condensation of evaporating Gd atoms within inert gas atmosphere. The microscope analysis, based on both measurements of small angle X-ray scattering (SAXS), X-ray diffraction (XRD), Raman scattering spectrum (RSS) and observation of transmission electron microscope (TEM), have been carried out in order to evaluate the size and its distribution of as-prepared nm-Gd powders. It turns out that the size distribution of nm-Gd powders meets very well with the distribution function of Rayleigh instead of logarithm. The mean size of nm-Gd powders shows a linear relationship with inert-gas pressure as follows:D=a+blnP. A discussion concerning the influence of particle size of nm-Gd powders on nanometer material parameters such as size distribution, specific surface area and percentage of surface atoms have been given in detail.
Key words: rare earth nanometer materials microscope analysis