Structural, thermal and magnetic properties of Fe-Si-B-P-Cu melt-spun ribbons: Application of non-isothermal kinetics and the amorphous random anisotropy model

The microstructural variation of Fe-Si-B-P-Cu melt-spun ribbons was analyzed on the basis of non-isothermal kinetics and the amorphous random anisotropy model. The magnitude of latent heat of the crystallization process obtained from DSC curves increases with the increase of quenching wheel speed. The apparent activation energies of the nucleation and growth of α-Fe nanocrystallites increase as the quenching wheel speed increases. Thermal analysis implies that the size of the local short-medium order (cluster) in melt-spun ribbons reduces with the increase of quenching wheel speed. Meanwhile, magnetic measurements display that the coercivity of the stress-released ribbons decreases with the increasing quenching wheel speed. This confirms the thermal analysis results on the basis of the amorphous random anisotropy model. Combing thermal analysis with magnetic measurements, it is believed that the cluster size of the melt-spun ribbons decreases with the increase of the cooling rate during melt-spinning process. Nanocrystalline alloy with desirable microstructure and soft magnetic properties is anticipated to be obtained from an amorphous alloy prepared at an appropriate cooling rate by adjusting the quenching wheel speed.