Recent Advances in Hot-Press Sintered FeSi-Based Soft Magnetic Composites

Soft magnetic composites (SMCs) are widely used in electromagnetic devices such as motors, transformers, sensors, and inductors due to their high saturation magnetization, high permeability, low coercivity, and reduced core loss. To meet the increasing demand for high-frequency applications, SMCs require high permeability and low core loss. In recent decades, various Fe-based alloy particles (e.g., FeSi, FeCo, FeSiAl, FeNi, and amorphous alloys) have been coated with high-resistivity insulating layers to form core–shell structures. Among these, FeSi has attracted significant attention. Several strategies have been explored to improve the magnetic performance of SMCs; however, advanced compaction techniques have proven particularly effective. This review highlights the role of hot pressing in the fabrication of FeSi-based SMCs and discusses key factors for optimizing microstructure, enhancing magnetic coupling, and reducing porosity for advanced electromagnetic applications.