Design of Insulation Layer Structures in 3-Dimensional Fe-6.5%Si Cores via Dual-nozzle Material Extrusion combined with Spark Plasma Sintering technology

We present a novel hybrid manufacturing approach that combines dual-nozzle material extrusion and spark plasma sintering to fabricate metal–insulator–metal-structured Fe-6.5 wt.% Si (Fe-6.5Si) magnetic cores. This process integrates MgO-B2O3-SiO2 (MBS) insulation layers to achieve enhanced bonding between the layers. The manufacturing process involved integrating MBS insulation for structural integrity, reducing the Fe-6.5Si layer thickness for frequency stability, and applying a post-heat treatment to improve magnetic performance. The MBS insulation system demonstrated sinterability, forming stable interfaces with the Fe-6.5Si layers. Through experimental investigation, we found that a Fe-6.5Si layer thickness of 0.6 mm combined with 0.2-mm MBS insulation layers exhibited promising frequency stability up to 1 kHz. Additionally, post-heat treatment at 1200 °C enhances the magnetic properties by increasing the permeability and reducing hysteresis loss through grain growth and interface modification. This manufacturing approach has the potential to produce high-performance magnetic cores while offering design possibilities for fabricating various part geometries compared with conventional methods.