Improved magnetic and thermal conductivity performance of FeSi soft magnetic composites by adding h-BN

Low heat generation and high thermal conductivity are the basic guarantees for stable operation of magnetic devices. In this paper, h-BN nano-sheet were coated on FeSi particles to prepare FeSi/h-BN magnetic cores with a low loss and high thermal conductivity. The surface modified h-BN evenly coated on FeSi particles improved the insulation between magnetic particles. Appropriate amount of h-BN sheet addition effectively reduced the eddy current loss and improved thermal conductivity of FeSi soft magnetic composites (SMCs), which can be attributed to the high resistivity and high planar thermal conductivity of h-BN nano-sheet. The FeSi SMCs with 3 wt% h-BN has the optimum comprehensive properties, effective permeability of 57, saturation magnetization of 172.2 A.m²/kg, low core loss of 601.6 mW/cm³ at 60 mT and 100 kHz, and its thermal conductivity increased by 62 % to 11.03 W m^-1K⁻¹, which is useful for the stable operation of devices.