Journal Of Metallurgical and Materials Engineering

Journal Of Metallurgical and Materials Engineering

Effect of Annealing Temperature and Time on The Magnetic Behavior of Nd-Fe-B Alloy Ribbons Produced by Melt Spinning Method

Document Type : Original Articles

Authors
Ghader Ahmadpour 1
Farzad Nasirpouri 2
1 Materials Engineering, Faculty of Mechanical and Metallurgical Materials Engineering, Birjand University of Technology, Birjand
2 Materials and Metallurgy Faculty , Sahand University of Technology, Tabriz
10.22067/jmme.2026.97524.1242
Abstract
In this research, the effects of annealing temperature and time on the magnetic properties, microstructure, and phase composition of Nd Fe B alloy ribbons produced by the melt spinning method were investigated. X ray diffraction (XRD), field emission scanning electron microscopy (FE SEM) coupled with energy dispersive spectroscopy (EDS) and elemental mapping, as well as vibrating sample magnetometry (VSM), were employed on samples annealed at three different temperatures (550, 650, and 700 °C) for 30, 60, and 90 minutes. XRD results indicated that the as cast (non annealed) sample exhibited a predominantly amorphous structure. Upon annealing at 650 °C, the hard magnetic phase Nd₂Fe₁₄B was formed. At 700 °C, secondary phases such as α Fe and NdFe₄B₄ also appeared in addition to the main phase. FE SEM micrographs confirmed the gradual grain growth with increasing temperature and time. EDS analysis and elemental mapping verified a uniform elemental distribution at 650 °C. Analysis of hysteresis loops revealed that the sample annealed at 650 °C for 90 minutes exhibited the highest coercivity (Hc = 8710 Oe) and squareness ratio (Mr/Ms = 0.781). These results indicate that, under these conditions, a stable nanocrystalline structure, effective domain wall pinning, and appropriate exchange coupling collectively yield the most favorable magnetic properties. Conversely, at 700 °C, magnetic properties deteriorated due to grain coarsening and the presence of soft magnetic phases. In general, annealing at 650 °C for 90 minutes was identified as the optimum condition for achieving desirable magnetic properties while preserving the nanocrystalline structure.
Keywords
Nd-Fe-B alloy
melt-spun ribbons
annealing treatment
Nd₂Fe₁₄B phase
microstructure
magnetic properties
Subjects
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