Crystallization and Magnetic Property of FeCoZrB Alloy

Samples of the nanocrystalline soft magnetic alloy Fe42Co42Zr7B9 were prepared by annealing the as-quenched amorphous precursors at various temperatures to investigate the crystallization behavior of the samples and the evolution of their magnetic properties. Differential scanning calorimetry revealed two distinct stages, namely (i) the primary crystallization of the α-Fe solid solution and (ii) the formation of ZrCo3B2 and Fe3Zr phases. Grain growth proceeded gradually in the early stage and increased rapidly in the later stage of crystallization. The lattice constant initially increased and then decreased at about 600°C due to the incorporation of~Zr into the α-Fe lattice. The specific saturation magnetization (Ms) and coercivity (Hc) followed similar two-stage trends, i.e., Ms first increased and then decreased, while Hc slightly increased below 600°C and rose sharply thereafter due to grain growth and phase transformations. Thus, precise control of the annealing temperature in FeCoZrB alloys allows for tuning of the microstructural and magnetic properties, offering pathways toward high-efficiency, soft magnetic components.