介质环境对铜丝电爆炸制备纳米粉体的影响

为了探究介质环境对电爆炸制备纳米粉体的影响, 搭建了相应的电爆炸实验平台, 以铜丝为例分别在水和不同空气压力下开展了电爆炸制备纳米粉体实验.通过Rogoswki线圈和高压探头分别测试了电爆炸过程中的电流和电压波形图.通过电压、电流及能量沉积特征分析了电爆炸的基本过程以及介质环境在电爆炸过程中的作用.运用透射电子显微镜对爆炸产物进行了粒度分析.研究发现, 介质环境对于电爆炸过程的影响主要表现在汽化化阶段以后, 包括介质对蒸汽膨胀的抑制作用, 介质的电离对于铜丝表面击穿的影响以及其对高温金属蒸汽及等离子体的冷却作用.水中铜丝电爆炸能够制备局部均匀的小尺寸纳米粉体, 粒度多数集中在10–20 nm之间, 但粉体易积聚, 且整体粒度跨越较大.空气中制备的粉体分散良好, 符合对数正态分布, 基本上分布于20–100 nm之间, 平均粒度约为40 nm.

Effect of medium on nanopowders prepared by Cu wire electrical explosion

To analyze the influence of environmental media on nanopowders prepared by electrical explosion method, electrical explosion experiment is carried out using copper wire under water and different air pressures. Voltage and current waveforms are measured by Rogowski coil and high-voltage probe. The basic process of electrical explosion and the function of environmental media in the course of electrical explosion are analyzed by combined characters of the voltage, current, and energy deposition. The particle size of explosive products is analyzed by transmission electron microscopy. Results show that it is mainly after the vaporization stage of the copper wires that the medium may affect the formation of the products. Effects of the medium on the electric explosion of metal wires include the restriction of the medium on the expansion of the metal vapor, the influence of the medium ionization on breakdown of the copper surface as well as the cooling of the copper vapor and the plasma. For the water medium, the diameter of the products distributes in a wide range but is mainly in the range about 10 to 20 nm, while in the air medium, the average particle size is about 40 nm, basically ranging from 20 to 100 nm.