| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 237188 | Powder Technology | 2012 | 6 Pages |
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.
Graphical abstractA fractured NdFeB particle after pressing at 800 MPa whose exposed uncoated surfaces reduce the performance of NdFeB bonded magnets.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pressing affects microstructure and aging of NdFeB-based bonded magnets. ► Uncoated surfaces are exposed due to fragile fracture of the particles. ► Magnetic performance is reduced by 19% after aging in air. ► Pressing reduces Nd2Fe14B lattice parameter and causes macro elastic stress. ► An aging/curing step during 24 h is able to relief such macro-elastic stress.
