A Study Of Fabricating High-Melting-Point Nano Niobium Colloid By Micro-EDM

This study presents, for the first time, the successful fabrication of a nano-niobium colloid using a laboratory-developed micro electrical discharge machining (micro-EDM) system. A systematic comparison was conducted to evaluate the colloid’s particle size distribution and suspension stability under different dielectric fluids. By employing the electrical spark discharge method at ambient temperature and atmospheric pressure, nano-niobium colloids were synthesized under varying process parameters using two different dielectric fluids. In this process, deionized water and distilled water served as the dielectric media. The high-temperature arc discharge melted the metal material, and the detached fragments combined with the dielectric fluid to form nano-sized colloidal particles. The fabricated samples were analyzed using UV-Vis spectroscopy and a Zetasizer to verify the effects of different dielectric fluids on the fabrication outcomes. The fabrication voltage was fixed at 140 V, the dielectric fluid volume was maintained at 120 mL, and the discharge duration was set to 3 minutes. When deionized water was used as the dielectric fluid and the discharge pulse duration (Ton-Toff) was set to 60–60 μs, the resulting colloid exhibited a characteristic absorption peak at 192 nm with an absorbance of 0.286. The average particle size was measured to be 64.92 nm, and the zeta potential was recorded as −58.3 mV. Similarly, when distilled water was used under the same discharge conditions, the colloid exhibited a characteristic absorption peak at 192 nm with an absorbance of 0.159. The average particle size was measured to be 58.38 nm, and the zeta potential was recorded as −53.0 mV. The fabrication of nano-niobium colloids using the electrical spark discharge method is simple and rapid, requiring no additional chemical reagents. This process minimizes environmental and human health hazards to effectively zero during fabrication.