电爆炸法制备Fe3O4纳米颗粒及其物相研究

搭建了电爆炸金属丝实验平台，在空气中电爆炸铁丝来制备纳米金属颗粒。利用电阻分压器与Rogowski线圈来测量电爆炸过程中铁丝上的负载电压与电流。将负载电压与电流之积进行时间积分来估算沉积在铁丝上的能量。使用光电探测器对电爆炸过程中产生的等离子体发光信号进行探测。对铁丝电爆炸后形成的产物使用高倍显微镜、扫描电镜（SEM）、透射电镜（TEM）、能谱分析仪（EDS）以及X射线衍射仪（XRD）进行观测，来研究其物相特性。实验结果表明:电爆炸过程中，当铁丝由液相变为气相时，其电阻急剧增加，因此电流几乎不能流过铁丝，同时铁丝上的负载电压会趋近于电容器的初始充电电压。随着能量的持续积累，等离子体在爆炸腔中形成。由于原本被阻断的电流能够从低电阻等离子体中流过，因此电压电流波形变为欠阻尼波形。电爆炸铁丝所得的产物为Fe3O4纳米颗粒，其中大部分呈规则的球形。Fe3O4纳米颗粒的粒径主要分布在30~60 nm之间，并且符合对数正态分布。

Phase analysis of Fe3O4 nanoparticles produced by electrical explosion of iron wire

The experimental platform for electrical explosion of wire was built and iron wire was electrically exploded in air to produce metal nanoparticles. The total energy deposited in the wire was estimated by time integration using the product of voltage and current waveforms measured by voltage divider and Rogowski coil, respectively. The light emission from the plasma was recorded by photoelectric detector. The composition and morphology of the electrical explosion product were tested by the high-multiple microscope, scanning electronic microscope (SEM), transmission electron microscopy (TEM), the energy dispersive spectroscope (EDS) and X-ray diffractometry (XRD) to analyze the products phase characteristics. The results show that during the process of electrical explosion, when iron wire goes from liquid phase to gas phase, current hardly flows through the wire and load voltage of wire approaches the initial charge voltage of capacitor due to rapid increase of wire resistance. With energy deposited into wire, arc plasma is formed in the chamber. Meanwhile, current can flow through the low resistance arc plasma, which leads to voltage as well as current waveforms evolving into underdamped sinusoidal waveforms. The product of iron wire electrical explosion is composed of Fe3O4 nanoparticles and most of them are in good spherical shape. The particle size ranges mainly from 30 to 60 nm and obeys the log-normal distribution.