纳米稀土金属Gd的制备及其粒径评估

PREPARATION AND SIZE EVALUATION OF NANOMETER GADOLINIUM POWDERS

采用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（ＴＥＭ）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体系的比表面积、表面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。

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+b ln P. 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.