Ferromagnetic composites with polymer matrix consisted of nanocrystalline F...: EBSCOhost
Objective The paper intends to present structural and magnetic behavior of ferromagnetic composites consisted of nanocrystalline powders obtained by annealing and milling of Fe 78 Si 9 B 13 and Fe 73,5 Cu 1 Nb 3 Si 13,5 B 9 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. [ABSTRACT FROM AUTHOR]
