【摘要】 采用超声波对金属Ag盐溶液的直接超声作用,利用超声波产生的声空化效应、声流效应和非线性交变振动效应使水分子被激活,产生还原性的H·、水合eaq-和氧化性的·OH,利用H·和eaq-的还原性实现金属Ag离子的被还原。实验结果发现,PVP的存在可以明显地降低还原Ag粒子的大小和减小粒度分布范围;利用TEM对还原金属Ag粒子的生成过程和分形生长进行观测;运用分形理论,定性解释了在超声条件下金属Ag粒子的分形生长过程和树枝晶产生的原因,并利用盒维数法求出晶形分形生长过程中的分形维数,其分形维数在1.8~1.9之间。更多还原

【Abstract】 Nano-particles of silver were prepared by direct action of ultrasonic upon the silver salt solutions in this paper. H·, OH· and hydrated electrons were generated under the acoustic effects of cavitations, streaming as well as nonlinear alternating vibration, and then Ag+ was reduced by H· and the hydrated electrons. It was found that PVP existing in the solutions noticeably diminished the sizes and its distributions of Ag particles. The growth processes and fractals of Ag particles were observed using transmission electron microscopy analysis. The growth process and the reasons to form dendrites were qualitatively explained using fractal theories. The fractal dimension of the dendrites was calculated as 1.8~1.9 using the box-counting dimension method.更多还原