Synthesis of small-sized spherical Fe-based amorphous powders with insulating nanolayer from ribbon electrodes

Abstract

With growing demand for high-frequency electronic components in modern 5 G and ongoing 6 G communication networks, advanced soft-magnetic composites (SMCs) are crucial in diverse applications of electronic products and power systems. A novel spark erosion approach using ribbon electrodes was developed to produce fine Fe-based amorphous powders with high sphericity (99.5 %) and controllable particle sizes (D₅₀ ≤ 5.9 μm). The use of ribbon electrode leads to a significant enhancement of powder production efficiency, approximately four times than that achieved using bulk electrodes employed in conventional spark erosion. An oxygen-rich nanolayer was formed in-situ on the powder surface with high resistivity, eliminating the subsequent complex insulating treatment in traditional SMCs production. The SMCs made of our small-sized spherical insulated powders demonstrated stable permeability at high frequency, relatively high saturation magnetization, and low core losses. These performances meet the urgent soft-magnetic requirements essential for the miniaturization and high-frequency applications of electronic devices. The novel spark erosion method for preparation of fine spherical amorphous and crystalline powders with excellent soft-magnetic properties holds paramount importance for the manufacturing of high-performance SMCs as advanced electronic components.