High resolution scanning electron microscopy study on sintered and cast NdFeB magnets

Author

Li, L. ; Ma, B.M. ; Bounds, C.O.

Author_Institution

Dept. of Mater. Sci. & Eng., Pennsylvania Univ., Philadelphia, PA, USA

Volume

29

Issue

6

fYear

1993

fDate

11/1/1993 12:00:00 AM

Firstpage

2983

Lastpage

2985

Abstract

By using a field-emission gun scanning electron microscope, the microstructural details in sintered and cast NdFeB magnets can be revealed either at high resolution (below 50 nm) or at low magnification (100 X) to view a larger area. In all sintered NdFeB based magnets, many Nd₂O₃ particles about 1 μm in diameter are found. The Nd-rich phase is not limited to the Nd₂Fe₁₄B (2-14-1) grain boundaries; some areas of this phase have dimensions similar to those of the 22 m-14-1 grains. The microstructure of cast NdFeB-based alloys strongly depends on the doping elements. An alloy containing Co and V shows a dendritic Fe-V primary phase with long thin 2-14-1 grains, while an alloy containing Co and Nb shows larger 2-14-1 grains with all phases in the ingot corresponding to phases in the sintered magnets

Keywords

boron alloys; ferromagnetic properties of substances; grain boundaries; iron alloys; neodymium alloys; permanent magnets; scanning electron microscope examination of materials; sintering; Nd₂O₃ particles; NdFeB; dendritic Fe-V primary phase; doping elements; grain boundaries; microstructural details; permanent magnets; scanning electron microscopy; sintered magnets; Cobalt alloys; Doping; Grain boundaries; Iron; Magnetic force microscopy; Magnets; Microstructure; Neodymium; Niobium alloys; Scanning electron microscopy;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.280896

Filename

280896