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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The effects of the pressing step on the microstructure and aging of NdFeB bonded magnets

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Author(s):
Perigo, E. A. [1] ; de Campos, M. F. [2] ; Faria, R. N. [3] ; Landgraf, F. J. G. [1, 4]
Total Authors: 4
Affiliation:
[1] Inst Technol Res IPT, BR-05508901 Sao Paulo - Brazil
[2] EEIMVR Fed Fluminense Univ, BR-27255125 Volta Redonda, RJ - Brazil
[3] Nucl & Energy Res Inst IPEN, BR-05508000 Sao Paulo - Brazil
[4] Univ Sao Paulo, BR-05508901 Sao Paulo - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Powder Technology; v. 224, p. 291-296, JUL 2012.
Web of Science Citations: 10
Abstract

The effects of the compaction step on the (micro)structural features and aging behavior of polymer coated NdFeB-based bonded magnets is reported. Due to the fracture of the material during pressing, it is estimated an increase of at least 14% in the particles' area which is not coated. Such uncoated surfaces, when exposed to the environment, reduce the magnetic performance of the magnets aged/cured in air by 19% in the conditions evaluated in this investigation. Furthermore, XRD results interpreted by Rietveld analyses show a lattice parameter change in the tetragonal structure of the hard magnetic phase after pressing. Such change varies as a function of the height of the compacted part and it is ascribed to macro-elastic stress arising from the pressure distribution in the magnet. An aging/curing step during 24 h is able to relief such macro-elastic stress. (C) 2012 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 10/08018-8 - Reprocessing of commercial REFeB (RE = Nd or Pr) sintered magnets for preparation of bonded magnets and semi-hard magnetic compounds using hydrogen
Grantee:Élio Alberto Périgo
Support Opportunities: Scholarships in Brazil - Post-Doctoral