Ferromagnetic composites with polymer matrix consisted of nanocrystalline Fe-based filler

Objective: The paper intends to present structural and magnetic behavior of ferromagnetic composites consisted of nanocrystalline powders obtained by annealing and milling of Fe₇₈Si₉B₁₃ and Fe_73,5Cu₁Nb₃Si_13,5B₉ metallic glasses. Methods: The as-cast ribbons were subsequently milled using a high-energy ball mill. The prepared powders were separated into fractions with a particle mean diameter range of 200–500 µm, 75–200 µm and 25–75 µm and then annealed to obtain the nanocrystalline powder materials. The powder particles were mixed and consolidated with a polymer to obtain composites in the form of the toroidal cores. The following experimental techniques were used: scanning and transmission electron microscopy, X-ray diffraction and vibration sample magnetometry. Results: The analysis of magnetic properties of the powders and the composites prepared from the powders revealed that the preparation process caused significant decrease in magnetic properties in a relation to ribbons in as-cast state. Conclusion: The structure and magnetic properties of the examined materials could be improved by means of a right choice of milling time as well as a thermal treatment and by a decrease of the demagnetization effect. Practice implications: The amorphous and nanocrystalline powders obtained by a milling of metallic glasses are an alternative to solid alloys and make it possible to obtain the ferromagnetic nanocomposites with controlled magnetic properties. - Highlights: • Soft magnetic composites consisting nanocrystalline powders were obtained. • Amorphous Fe₇₈Si₉B₁₃ and Fe_73,5Cu₁Nb₃Si_13,5B₉ ribbons were milled. • Powders particles were consolidated with polymer to obtain toroidal composites. • Magnetic properties could be formed by milling and annealing parameters. • Polymer nanocomposites with Fe-based powders are an alternative to solid alloys