# Performance Enhancement of Amorphous Soft Magnetic Composites by Synergistic Warm Compaction and Fine FeNi Powders Addition

## TL;DR

This paper introduces a new method to improve magnetic materials used in electronic devices by combining warm compaction with fine FeNi powders, resulting in better performance and lower losses.

## Contribution

A synergistic warm compaction and FeNi powder addition strategy is introduced to enhance amorphous soft magnetic composites without post-annealing.

## Key findings

- Warm compaction with FeNi particles increases composite density and improves magnetic properties.
- Optimal FeNi content of 30 wt% boosts effective permeability by 55.4% and reduces core loss by 21.8%.
- The method achieves excellent DC-bias performance and frequency stability for high-power applications.

## Abstract

Molded inductors play a critical role in a wide range of power electronic devices, where soft magnetic composite materials serve as the key functional component. This study proposes a synergistic optimization strategy, which integrates warm compaction molding with FeSiBCCr/FeNi composite powder, to enhance the overall performance of FeSiBCCr-based amorphous soft magnetic composites (ASMCs) without requiring post-annealing treatment. The results demonstrated that the warm compaction process facilitates effective particle rearrangement, enabling fine FeNi particles to efficiently fill the voids among the large amorphous particles. Moreover, the plastic deformation of FeNi particles during compaction contributes to a significant increase in the density (ρc) of the composite, thereby reducing pore-induced magnetic domain wall pinning and substantially improving the soft magnetic properties. With an optimal FeNi content of 30 wt%, the FeSiBCCr/FeNi compound ASMCs exhibit excellent performance. Compared to cold-pressed soft magnetic composites without FeNi fine powder, the effective permeability (μe) increases by 55.4% to reach 20.6, with excellent frequency stability. Under the condition of 100 kHz and 50 mT, the total core loss (Pcv) is reduced by 21.8% to 285.6 kW/m3. The DC-bias performance (μ% @ 100 Oe) achieves 94.5%. This study has successfully addressed the key technical challenges hindering the development of the compound ASMCs with high permeability and low core loss for molded inductors, thereby providing a practical and scalable material solution for advanced high-frequency and high-power electronic applications—particularly in emerging domains such as new energy vehicles and artificial intelligence systems.