摘要
采用小角x射线散射(SAXS)方法,对两类具有代表性的纳米团聚的生长分形进行了表征.一类为用化学方法(水合肼溶液还原法)制备的纳米金属Ni粉;另一类通过物理方法(纳米晶化处理),由非晶基体相中生长纳米晶相、形成非晶纳米晶双相结构的Finemet(Fe73.5Cu1Nb3Si13.5B9)合金.上述两类材料的纳米团聚在生长过程中都存在明显元素扩散迁移,形成在1—100nm范围内的元素分布非均匀区域.这些元素分布的非均匀区域具有多重质量生长分形特征,其尺度大小和分布方式对最终的材料的物理性能至关重要.SAXS方法是表征这类具有分形生长特征的纳米团聚微观结构信息的强有力手段.从方法论的角度详述了从SAXS测量到获得多重分形谱的处理过程,这一实验研究分析手段对于定量考察纳米微结构形貌的生长机理和性能的其他研究课题有一定的帮助作用.
Small angle x-ray scattering (SAXS) method was adopted to investigate the characteristics of growth fractal of two sorts of typical nanoscaled clusters, i.e. growing in both ultrafine Ni powders synthesized by chemical reaction and Finemet ( Fe(73.5) Cu(1) Nb(3) Si(13.5) B(9)) amorphous ribbon by physical crystallization annealing. The SAXS measurement discloses definitely the existence of distinct mass multifractal patterns within ultrafine Ni granules and crystallizing Finemet ribbon. The multifractal spectra of the clusters mentioned above suggest the occurrence of inhomogeneous distribution of constituent elements and growth fractal during the formation of those nanoscale clusters. The multifractal spectra of ultrafine Ni powders prepared using a variety of procedures take on an obvious difference in shape, indicating the substantial influence of preparation process on diffusion of constituent elements and the growth mechanism of clusters. The crystallization annealing processes, however, affect the multifractal spectra of Finemet alloy slightly.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第7期3290-3296,共7页
Acta Physica Sinica
基金
广东省自然科学基金(批准号:031554)
广州市纳米专项基金(批准号:2001212401)资助的课题.~~
