Regulation of magnetic and electrical performances in core-shell-structured FeSiCr@BaTiO3 soft magnetic composites

Abstract

Soft magnetic composites (SMCs) are extensively used for designing and manufacturing high-performance electronic devices, such as inductors, filters, mutual inductors and chokes, owing to their high effective permeability (μe) and stable magnetic properties. However, the production of SMCs that meet the demands of high resistivity, high effective permeability (μe), and low core losses (Pcv), which are required for high-frequency miniaturized electronic systems, is challenging. In this study, we improve the electromagnetic performance of SMCs by coating FeSiCr metal particles with BaTiO3 dielectric ceramic powder at various concentrations (0.00–3.75 wt%). The micro-morphological, static magnetic, resistivity (ρ), and core loss (Pcv) properties of FeSiCr@BaTiO3 SMCs are comprehensively investigated. Energy dispersive spectroscopy elemental distribution mapping is used to confirm the formation of core-shell structures with excellent coating quality. With an increase in the BaTiO3 dielectric powder content, the core losses, Pcv (at 800 kHz, 10 mT and 25 °C), initially decrease and subsequently increase, and comprise hysteresis losses (Ph) and eddy current losses (Pe). Moreover, owing to the introduction of the non-magnetic-phase BaTiO3 powder, hysteresis losses increase monotonically, whereas eddy current losses exhibit the opposite trend. The FeSiCr@BaTiO3 SMCs with 2.25 wt% BaTiO3 dielectric ceramic powder exhibit outstanding comprehensive electromagnetic properties with an effective permeability of μe = 48, saturated magnetization of Ms = 115 emu/g, core losses of Pcv = 42 mW/cm3 (at 800 kHz, 10 mT and 25 °C), and resistivity of ρ = 2.74 × 105 Ω∙m. These state-of-the-art FeSiCr@BaTiO3 SMCs present considerable potential for application in high-performance power devices and components.