Improved high-frequency magnetic properties of FeSiBCCr amorphous soft magnetic composites by adding carbonyl iron powders

Abstract

The rapid development of mobile communication, electronics and electronics has put forward higher requirements on the permeability, core loss and DC bias performance of soft magnetic materials. In order to prepare soft magnetic materials with excellent high-frequency properties, FeSiBCCr amorphous powders produced by gas-water combined atomization were mixed with the CIP (carbonyl iron powder), and the toroidal SMCs (soft magnetic composites) were prepared by the phosphate and EP (epoxy resin) co-coated FeSiBCCr/CIP hybrid powders. The effects of EP and CIP content on soft magnetic properties of the SMCs were investigated. When the EP content was increased from 1 to 3wt%, the insulated coating effect and density of SMCs were significantly improved, resulting in decreased core losses and increased permeability. Although the DC bias performance of SMCs deteriorated slightly after adding the small-size CIP, the consequent reduction in the air gaps between amorphous particles led to a significant increase in the density and permeability of SMCs. When the CIP content was 0∼20wt%, core losses decreased with the increase of CIP due to the decreased average particle size; when the CIP content was 20∼70wt%, core losses increased rapidly with the increase of CIP content due to the continuous decrease of resistance and the increase of coercivity. Under the condition of 20wt% CIP and 3wt% EP, the FeSiBCCr/CIP SMCs exhibited a high permeability of 30.9 ± 0.6 and a high DC bias% of 91.8 ± 0.2 at a DC magnetic field of 71.25 Oe. Core losses of the SMCs were 50.6 ± 13.4 mW·cm–3 (at 0.05 T and 100 kHz) and 850.0 ± 11.8 mW·cm–3 (at 0.02 T and 1000 kHz), which were decreased by 64.8% and 27.9% compared to that without adding CIP. The FeSiBCCr/CIP SMCs shows excellent DC bias performance and low core losses, which indicates great potential in the electronic and electrical application.