Magnetic properties of mechanically-alloyed Sm-Co nanophase hard magnets

Author

Gallagher, K. ; Venkatesan, M. ; Coey, J.M.D.

Author_Institution

Dept. of Phys., Trinity Coll., Dublin, Ireland

Volume

37

Issue

4

fYear

2001

fDate

7/1/2001 12:00:00 AM

Firstpage

2528

Lastpage

2530

Abstract

Highly coercive Sm₁₄Co₈₆ powders were prepared by mechanical alloying with a view to enhance the high temperature magnetic properties by optimizing the annealing conditions. The powders were annealed in quartz tubes with a continuous vacuum of ~10^-6 mbar at different temperatures. X-Ray diffraction studies confirmed the formation of a disordered 2:17 phase. DTA measurement on the as-milled amorphous powders revealed a single crystallization event at around 500°C. Magnetic measurements showed room temperature coercivities of at least 1 T and Curie temperatures around 820°C. The behavior of the initial magnetization curve lies in between those observed for low H_c 2:17 precipitation hardened magnets and SmCo₅ or Nd₂Fe₁₄B magnets. The magnitude of coercivity is found to be sensitive to annealing temperature. The detailed comparison of magnetic properties with annealing conditions will be presented

Keywords

Curie temperature; X-ray diffraction; annealing; cobalt alloys; coercive force; crystallisation; differential thermal analysis; ferromagnetic materials; magnetisation; mechanical alloying; nanostructured materials; permanent magnets; samarium alloys; Curie temperature; DTA; Sm-Co nanophase hard magnet; Sm₁₄Co₈₆; Sm₁₄Co₈₆ powder; X-ray diffraction; annealing; coercivity; crystallization; disordered 2:17 phase; high-temperature magnetic properties; magnetization; mechanical alloying; Alloying; Amorphous materials; Annealing; Coercive force; Electron tubes; Magnetic properties; Magnets; Powders; Temperature; X-ray diffraction;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.951224

Filename

951224