Solid solution characteristic and magnetic evolutions of nanostructured cobalt-based Co–Fe–Zr–Nb–B alloy

This research investigated the magnetic, microstructure, and thermal behavior of Co₄₉Fe₂₁Zr₁₀Nb₅B₁₅ alloyed powder prepared by ball milling method. The milled samples were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, differential scanning calorimetry, and vibrating sample magnetometry. The results demonstrated that after 40 h of milling, an iron-based solid solution phase began to form, ultimately leading to a partially solid solution with undissolved zirconium and cobalt after 180 h. The final average crystallite size reached 23 nm with a mean particle size of about 3.4 μm. The saturation magnetization of the final sample was relatively high compared to previous reports. Coercivity values showed a continuous increase from 40 to 180 h of milling time. The thermal analysis of the alloy sample exhibited three exothermic peaks, providing insights into the phase transformations of the alloy. The findings indicated soft ferromagnetic behavior, particularly for the annealed samples.