Preparation of Nanoiron Colloid Using Electrical Spark Discharge Method and Analysis of Its Properties

This study used electrical discharge machine (EDM) to prepare nanoiron colloid with the electrical spark discharge method (ESDM) in a preparation environment with normal temperature and atmospheric pressure. An iron wire with a diameter of 1mm and purity of 99.9% was used as the electrode materials, and deionized water (DW) was used as the dielectric liquid. This preparation process was simple and did not require chemical additives. This study used different pulse discharge cycles $(\mathrm{T}_{\mathrm{on}}:\mathrm{T}_{\mathrm{o}\mathrm{f}\mathrm{f}})$ to prepare nanoiron colloid for the purpose of exploring the optimal $\mathrm{T}_{\mathrm{on}}:\mathrm{T}_{\mathrm{off}}$ parameters for the preparation of nanoiron colloid. The particle size distribution and the zeta potential of the prepared nanoiron colloid were tested by a Zetasizer to analyze the particle size distribution and suspension ability. According to the test results, when the pulse discharge cycle $\mathrm{T}_{\mathrm{on}}:\mathrm{T}_{\mathrm{off}}$ was $10:40\mu \mathrm{s}$, the prepared nanoiron colloid had a size of 56.49nm and a zeta potential of 45.6mV, which indicates small particle size and optimal suspension stability. Therefore, $10:40\mu \mathrm{s}$ was the optimal preparation parameter. Finally, the optical properties, crystal structure, and hysteresis curve of the nanoiron colloid were analyzed by UV -Vis, XRD, and VSM.