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Improved thermal stability of hard magnetic properties in rapidly solidified RE–TM–B alloys

Published online by Cambridge University Press:  31 January 2011

Z.W. Liu ,
R.V. Ramanujan  and
H.A. Davies
Z.W. Liu*
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore; Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD, United Kingdom; and School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People’s Republic of China
R.V. Ramanujan
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
H.A. Davies
Affiliation:
Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD, United Kingdom
*
a)Address all correspondence to this author. e-mail: zwliu@scut.edu.cn, zwliu@ntu.edu.sg
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Abstract

Rapidly solidified nanocrystalline RE–TM–B (RE = Nd, Pr, Dy, TM = Fe, Co) alloys with enhanced hard magnetic properties were synthesized by melt spinning. The composition- and microstructure-dependent elevated temperature magnetic properties were investigated. The temperature coefficients of remanence (α) and coercivity (β) were determined. The effects of Pr substituting Nd, Co substituting Fe, Dy substituting RE, and grain size on the Curie temperature and thermal stability were studied. Co or Dy substitutions were found to have a significant beneficial effect on the thermal stability. Reducing grain size could also improve elevated temperature behavior. Maximum energy product (BH)max > 100 kJ/m3 could be obtained in compositionally optimized nanophase alloys at temperature of 473 K. Extremely low coefficients of α and β were realized in exchange coupled nanocomposite alloys. Bonded nanocomposite magnets with α = −0.052%/K and β = −0.0365%/K for 300–400 K were also successfully fabricated.

Keywords

Magnetic propertiesNanoscaleRapid solidification
Type
Articles
Information
Journal of Materials Research , Volume 23 , Issue 10 , October 2008 , pp. 2733 - 2742
Copyright
Copyright © Materials Research Society 2008

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