An Innovative Approach for Generation of Aluminium Nanoparticles Using Micro Electrical Discharge Machining

Abstract

Nanoparticles exhibit enhanced size dependant properties when compared to ultrafine or larger particles of the same material. Aluminium nanoparticles are used as ingredients in solid rocket propellant formulations and explosives. Aluminium nanoparticles are produced by various physical and chemical methods viz. wire explosion, laser ablation, combustion flame and aerosol synthesis, but micro-electrical discharge machining (micro-EDM) system has not yet explored to generate nanoparticles. This article presents the development of an innovative approach using the micro-EDM process to generate aluminium nanoparticles. Micro-EDM was performed with various operating parameters such as the voltage, current, pulse duration and duty cycle. In this proposed process, both cathode and anode made of aluminium, are melted and vaporized in DI water, used as a dielectric liquid. Meanwhile, the ultrasonic vibration is applied to remove the vaporized metal particles rapidly from the melting zone. The generated nanoparticles in the base fluid are characterized using transmission electron microscopy (TEM), energy dispersive analysis by X-rays (EDAX), selected electron diffraction pattern (SAED), optical absorption spectroscopy and dynamic light scattering technique (DLS) studies. The presence of FCC crystalline aluminium particles were verified by EDAX, SAED and absorption spectroscopy. The TEM results reveal that the particle sizes lies in the range of 50-130nm with average primary particle size of ∼ 90nm and the DLS analysis of particle size indicates that it follows normal distribution.