A study of the effects of Cu-addition on the annealing behavior and microstructures of Nd-Fe-B type sintered magnets

Author

Ragg, Oliver M. ; Harris, I.R.

Author_Institution

Sch. of Metall. & Mater. Sci., Birmingham Univ., UK

Volume

29

Issue

6

fYear

1993

fDate

11/1/1993 12:00:00 AM

Firstpage

2758

Lastpage

2760

Abstract

A high temperature homogenization treatment (1100°C for one hour) is applied to sintered magnets of Nd₁₇Fe_76.5B₅Cu_1.5. This is followed by a low temperature anneal (600°C for one hour). The magnetic properties of the samples are related to their microstructure. The formation of Nd₂Fe₁₇ during the homogenization and quench treatment is thought to be responsible for the fall in coercivity, and the increased remanence is attributed to an increased fraction of the Nd₂Fe₁₄B matrix phase. The subsequent anneal at 600°C causes the disappearance of most of the Nd₂Fe₁₇ phase and this corresponds with an increase in the coercivity. Quenching after the 600°C anneal gives better magnetic properties than slow cooling from this temperature. Furnace cooling the sample after homogenization results in the disappearance of the Nd₂Fe₁₇ phase and this treatment gives the highest coercivity and energy product

Keywords

alloying additions; annealing; boron alloys; coercive force; copper alloys; ferromagnetic properties of substances; heat treatment; iron alloys; neodymium alloys; permanent magnets; quenching (thermal); remanence; sintering; 1100 C; 600 C; Nd-Fe-B type; Nd₁₇Fe_76.5B₅Cu_1.5; Nd₂Fe₁₇ phase; annealing behavior; coercivity; high temperature homogenization treatment; low temperature anneal; magnetic properties; microstructures; permanent magnets; quenching; remanence; sintered magnets; Annealing; Coercive force; Cooling; Iron; Magnetic properties; Magnets; Microstructure; Neodymium; Remanence; Temperature;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.280921

Filename

280921