Effects of compaction and heat treatment on the soft magnetic properties of iron-based soft magnetic composites

Abstract

Iron-based soft magnetic composites (SMCs) are promising substitutes for laminate steels in electromagnetic applications due to their excellent magnetic properties and productivity. However, the preparation process is a key factor in deciding the magnetic performance of SMCs. In this work, the Fe-based soft magnetic composites with improved soft magnetic properties were achieved by optimizing the compaction and the annealing process. Results showed that the core-shell structure of powders which would directly have an impact on the permeability and the core loss of the SMCs could be affected by the compaction and the annealing process. In addition, the magnetic properties were enhanced by tuning the microstructure. As a result, the optimal magnetic performance of the compact with high permeability and low total core loss was obtained. The real part of the permeability of the soft magnetic composites could reach a maximal value of 336.8 and a rather low core loss of 2.5 W Kg −1 (measured at 50 mT and 5 kHz). Therefore, soft magnetic composites with enhanced magnetic properties were obtained by optimizing the powder metallurgy (PM) process in this study.

Effect of the Temperature on the Magnetic and Energetic Properties of Soft Magnetic Composite Materials

“…After the mixing process, the SMC powder was compacted through a hydraulic press. Two pressure levels are adopted in work: 400 MPa and 700 MPa [16,49]. The obtained shape is toroidal and is wound with two windings.…”

Effects of axial pressure on the evolution of core–shell heterogeneous structures and magnetic properties of Fe–Si soft magnetic powder cores during hot-press sintering

“…Core–shell heterostructures within SMPCs limit the induced current during AC magnetisation inside the insulating and conductive particles, reducing the eddy current radius and minimising energy loss. 11 To obtain high-performance SMPCs, the core–shell heterostructure should maintain its integrity and uniformity. However, as-developed oxide ceramic insulating materials, such as SiO 2 , MgO, ZrO 2 and Al 2 O 3 , are brittle and susceptible to fracture under high-pressure and temperature conditions, making the core–shell heterogeneous structure prone to destruction during sintering.…”

Hybrid Phosphate-Alumina Iron-Based Core-Shell Soft Magnetic Composites Fabricated by Sol-Gel Method and Ball Milling Method

“…Owing to their superior properties, including high permeability, high-frequency stability, 3D isotropy magnetic field, high productivity and, especially, the high electrical resistivity, iron-based soft magnetic composites (SMCs) with a special core-shell structure [3] have attracted broad academic interest and investigations in order to satisfy the requirements of applications in power electronics, transformers and electric motors at medium to high frequency [4,5]. The iron-based SMCs are conventionally prepared by coating insulating materials onto the pure iron matrix to block the path of closed-current loops and the compaction and annealing process [6]. Therefore, the selection of appropriate insulating materials with high electric resistivity and good adhesive strength is vital to minimize the eddy current loss of the SMC cores [7].…”