Preparation of alumina nanoparticles by electrical discharge machining

Alumina nanoparticles have been increasingly used in the areas of medicine, biochemistry and industry. A number of chemical methods have been used for the preparation of alumina nanoparticles, including the introduction of surfactants to improve the suspensivity of the nano-sized particles. In this study, alumina (Al₂O₃) nanoparticles have been fabricated by using Electrical Discharge Machining (EDM) in pure water, without any chemical additives. The size distribution and chemical composition of Al₂O₃ nanoparticles were examined by dynamic light scattering (DLS) and energy dispersive X-ray spectroscopy (EDS), respectively. The zeta potential and surface plasmon resonance of Al₂O₃ nanoparticles were studied using zetasizer and ultraviolet-visible (UV-Vis) spectroscopy. The experimental results show that Al₂O₃ nanoparticles, with particle sizes ranging from 12 nm to 32 nm (mean 22 nm), can maintain a stable suspension in water at room temperature. Zeta potential analysis showed that a positive charge (around 50 mV) on the particle surface may contribute to the stability of the suspension. The EDM, which is an alternative method for nano-sized Al₂O₃ component fabrication, provides several potentially distinct advantages, including: low cost, high speed, ease of use, and ability for mass production.