Optimizing Annealing Temperature Control for Enhanced Magnetic Properties in Fe-Si-B Amorphous Flake Powder Cores

Abstract

In this study, we examined the optimal pre- and post-annealing conditions for soft magnetic composites (SMCs) using amorphous flake powders produced through ball milling of amorphous Fe-Si-B ribbons, leading to enhanced magnetic properties. The SMCs, which utilized flake powders created via melt spinning, displayed outstanding DC bias characteristics, as well as increased permeability, primarily due to high saturation magnetization and the flaky morphology of the powders. Pre-annealing was performed not only to remove residual stress formed during the melt spinning process but also to improve pulverizing efficiency, which ultimately affected the particle size of the flake powders. Core annealing was performed to reduce core losses and improve permeability by relieving the residual stress generated during the pressing process. As a result, pre-annealing and core annealing temperatures were identified as crucial factors influencing the magnetic properties of the SMCs. We meticulously analyzed the particle size, the morphology of the flake powder, and the magnetic properties of the SMCs in relation to the annealing temperatures. In conclusion, we demonstrated that flake powder SMCs achieved superior soft magnetic properties, including significantly reduced core loss and heightened permeability, through optimal pre- and core-annealing at 370 °C and 425 °C, respectively.

Exploring the Impact of Different Milling Parameters of Fe/SiO2 Composites on Their Structural and Magnetic Properties

“…Soft magnetic composites (SMCs) represent a fast-growing subgroup of soft magnetic materials requiring relatively low investments for their production. In most cases, these materials are made from ferromagnetic powders milled in different types of mills under different conditions, which can be easily changed by using a different ball-to-powder ratio (BPR) [9][10][11]. The milled powders can be coated with an organic, inorganic, or organicinorganic coating to reduce eddy current loss.…”

Study on Compressibility According to Mixing Ratio and Milling Time of Fe-6.5wt.%Si

“…In general, microstructure is an important determinant of the performance of SMCs. Microstructure-related parameters include particle size and distribution, milling time, particle shape, porosity, coating thickness, and the presence or absence of a coating [6,7].…”