Effect of heat treatment on magnetic properties and microstructure of bulk Fe₃B/Nd₂Fe₁₄B nanocomposite permanent magnets

Abstract

Melt spun ribbons of Nd_4·5Fe₇₇B_18·5 alloy were consolidated into bulk permanent magnets by spark plasma sintering (SPS) method. Effects of heat treatment on the density, microstructure and magnetic properties of the magnets are studied. Further observation shows that the sample consolidated by SPS possesses ultrafine nanocrystalline structure and small fraction of amorphous phase. After proper heat treatment, magnets with fine crystal structure and good magnetic properties were obtained simultaneously. On the other hand, excessive grains growth, which will lead to undesirable magnetic properties, can occur due to improper heat treatment.

Keywords:

• FE3B/ND2FE14B
• NANOCRYSTALLINE
• HEAT TREATMENT
• SPARK PLASMA SINTERING