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

Autor(es)

Perigo, E. A. ^[1] ; de Campos, M. F. ^[2] ; Faria, R. N. ^[3] ; Landgraf, F. J. G. ^{[1, 4]}

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Powder Technology; v. 224, p. 291-296, JUL 2012.
• Citações Web of Science: 10

Resumo

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)

• Processo FAPESP: 10/08018-8 - Reprocessamento de ímãs sinterizados comerciais de TRFeB para a preparação de magnetos aglomerados e de compostos magnéticos semiduros utilizando hidrogênio
• Beneficiário: Élio Alberto Périgo
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado