Researchers at South China University of Technology, in collaboration with the Dongguan Institute of Materials Science and Technology, Chinese Academy of Sciences, have developed a novel supranano multi-precipitate microstructure in amorphous soft magnetic composites using Ar/O₂ plasma treatment. By facilitating magnetic-moment reversal, this approach significantly reduced the coercivity while maintaining excellent overall performance. The optimized material exhibits an ultralow coercivity of 0.13 Oe, an effective permeability of 37.3, a high saturation magnetization of 185 emu g-1 and an ultralow core loss of 191.18 kW m⁻³ at 1 MHz and 20 mT. These results provide for a promising strategy for developing next-generation soft magnetic composites for miniaturized, high-frequency, and high-efficiency power electronics devices.
Soft magnetic composites (SMCs) have attracted considerable interest for high-frequency power electronics devices because of their favorable magnetic properties. Fe-based amorphous alloys are particularly promising owing to their intrinsically low coercivity and core loss. However, achieving a simultaneous balance among saturation magnetization, effective permeability, and core loss remains challenging. he limited deformability of amorphous powders creates internal air gaps during compaction, weakening interparticle magnetic coupling and reducing effective permeability. Increasing the compaction pressure can improve density but also introduces internal stresses and magnetic-domain pinning sites, thereby increasing coercivity and hysteresis loss. Although conventional nanocrystallization can improve magnetic performance by controlling nanocrystal size and distribution, simultaneously optimizing these competing properties remains difficult. A simple microstructural strategy capable of combining high permeability and saturation magnetization with low coercivity and core loss is therefore highly desirable.
The Solution: The researchers developed a novel supranano multi-precipitate microstructure in amorphous soft magnetic composites using Ar/O2 plasma treatment followed by conventional cold compaction. The results indicate that the high-energy plasma induces the formation of ultrafine α-Fe, Fe3O4, SiO2, and Fe2O3 precipitates with sizes of only 0.8-2.5 nm, which are dispersed at the surface layer of amorphous powders. These supranano precipitates act as preferential nucleation sites for magnetic-moment reversal, facilitating magnetization reversal and substantially reducing coercivity. As a result, the optimized SMC achieves an ultralow coercivity of 0.13 Oe, and consequently, a high effective permeability of 37.3, a high saturation magnetization of 185 emu g-1, and an ultralow core loss of 191.18 kW m-3 at 1 MHz and 20 mT. These results highlight the great potential of supranano multi-precipitate engineering for balancing comprehensive magnetic properties in amorphous SMCs. This study introduces supranano multi-precipitate engineering as a new strategy for achieving a favorable balance of magnetic properties in amorphous SMCs.
The Future: Future research will focus on further improving the scalability of plasma-assisted processing for microstructure-property optimization and exploring its practical application in high-frequency magnetic components.
The Ar/O₂ plasma treatment provides a controllable surface-modification strategy for generating supranano multi-precipitate microstructures without altering the bulk composition of the amorphous powders. This characteristic may facilitate its integration into existing powder-processing workflows and eventual scale-up. Future studies will focus on improving the scalability of plasma-assisted processing and extending this concept to approaches such as plasma-assited ball milling to further optimize microstructure and magnetic performance.
The Impact: This work offers a promising strategy for achieving balanced magnetic performance inin amorphous SMCs and introduces a new concept for plasma-assisted microstructural engineering at the supranano scale. The approach could support the development of next-generation magnetic components, including high-frequency inductors, power chokes, and other miniaturized and high-efficiency power electronic devices.
The study was recently published online in Materials Futures, an international journal covering interdisciplinary materials science research.
Reference:
Jiwei Lv, Zhicheng He, Weisi Cai, Hongwei Ma, Tao Song, Pengxu Li, Luoxuan Hu, Haibo Ke*, Liuzhang Ouyang, Min Zhu, Weihua Wang, Chao Yang*. Supranano multi-precipitate balances comprehensive properties in amorphous soft magnetic composites. Mater. Futures 5 045102. DOI: 10.1088/2752-5724/ae9d2e
