氩气中铝丝电爆炸沉积能量对制备铝纳米粉体特性的影响

Effect of deposited energy of wire electrical explosion in argon on characteristics of synthesized aluminum nanopowders

研制了基于脉冲电容器放电回路的亚微秒金属丝电爆炸纳米粉体制备实验平台,包括电爆炸过程电流和电压测量系统。利用透射电子显微镜(TEM)观察纳米粉体的形态与结构,并通过电镜统计观察法分析TEM图像得到纳米粉体的粒度大小及其分布。在氩气中电爆炸铝丝制备铝纳米粉体,通过改变电容器充电电压,即初始储能,实验研究沉积能量对铝纳米粉体特性的影响规律。结果表明:铝纳米粉体颗粒形态与结构主要由氩气气压的高低决定,与沉积能量基本无关。增大丝爆过程的沉积能量可显著缩小铝纳米粉体粒度分布范围,减小颗粒平均粒径,并有效地抑制纳米粉体中亚微米颗粒的形成。随着沉积能量E与氩气气压p比值(Ep^(-1))增大,铝纳米粉体颗粒平均粒径、最大粒径和粒径大于100nm颗粒所占比例均呈指数函数单调减小。

The experimental equipment used for synthesizing nanopowders via the sub-microseconds electrical explosion of wire was built based on the short discharge circuit of a pulsed capacitor. The particle morphology of the nanopowder was observed by the transmission electron microscope （TEM）. The particle size and distribution of the nanopowders were obtained based on the statistics and observation of TEM images. Aluminum nanopowders were produced by electrical exploding aluminum wire in the argon gas, and the influence of the deposited energy on the characteristics of aluminum nanopowders was studied by changing the charging voltage of the capacitor. The results show that the morphology of aluminum nanopowders was mainly dependent on the argon gas pressure rather than deposited energy, and high deposited energy could also narrow the particle size distribution of alu minum nanopowders and reduce the count mean diameter of nanoparticles under the same argon gas pressure. It is indicated that charging voltage of the capacitor is an influential factor in eliminating submicrometer particles. The count mean diameter, the maximum diameter and the fraction of particles with diameter greater than 100 nm of aluminum nanoparticles decrease exponen- tially with the increasing expansion volume parameter （Ep-1 ）.