J. Bai, Z. Shi, Z. Wu, S. Jia
Xi’an Jiaotong University,
Keywords: aluminum nanoparticles, microsecond wire explosion, morphology, size distribution
Summary:Al nanoparticles have important applications in various fields, e.g., solid rocket propellant, explosives , electronics , detection of biomolecules , and enhancement of the properties of various nanocomposites [4-6], etc. Among various synthesis methods of nanoparticles, microsecond explosion of wires has drawn attention of many researchers due to its complicated physical process and various applications. When a high density pulsed current passes through a thin wire, it quickly melts, vaporizes and ionizes. The medium pressure and wire parameters have significant effect on the morphology and size distribution of the nanoparticles. The experiments are carried out in an explosion chamber with back-ﬂow rods around the explosion wire. The current is supplied by a capacitor bank with capacitance of 0.5-2 µF and are charged up to 20 kV. The diameters and lengths of the Al wires are 125, 200, 250 µm and 1, 2 cm, respectively. The explosion chamber is filled with air of different pressures less than 1 atm. The current and voltage waveforms are captured by a self-integrating Rogowski coil and a high voltage probe, respectively. The resistively voltage and deposited energy is calculated. The nanoparticles are collected on the surface of the monocrystalline silicon wafer. The morphology of the nanoparticles is acquired through the scanning electron microscope (SEM) and the size distribution of the nanoparticles is obtained. It is found that the nanoparticles are mostly spherical in shape. The size distribution becomes smaller and more centralized under higher deposited energy. It is unable to generate spherical nanoparticles under some threshold air pressure and the products appear to be a sputtering net structure on the silicon wafer. Finally, the relationships between the resistively deposited energy, the ambient pressure, the wire parameters and the characteristics of the nanoparticles are discussed.