Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Additive Manufacturing of Rare Earth Permanent Magnets: A Review on Laser Powder Bed Fusion (LPBF)
Submission Author:
Melissa Röhrig Martins Silva , SC
Co-Authors:
Melissa Röhrig Martins Silva, Rafael Gitti, Rubens Nunes de Faria Jr., fernando Landgraf, Cristiani Campos Pla Cid, Carlos Ahrens, Paulo Wendhausen
Presenter: Melissa Röhrig Martins Silva
doi://10.26678/ABCM.COBEM2021.COB2021-2090
Abstract
Additive Manufacturing (AM) emerges as an alternative technique to fabricate rare earth (RE) based bonded magnets, as reported by several authors, overcoming the challenges faced by conventional techniques in terms of geometrical limitations and possibly magnetic flux configuration. In the case of the Laser Powder Bed Fusion (LPBF) technique, one important challenge is to increase the magnetic flux density levels up to the commercially available injection molded ones, which stand out as a benchmark. This enhancement in magnetic performance can be attained by increasing magnetic properties such as remanence (Br) and consequently the energy stored per unit volume ((BH)max). Since Br values are proportional either to the density and magnetic texture level of the magnet, a practical approach is to increase both values once the current literature reports the obtention of highly porous and magnetically isotropic components. On Powder-based AM systems, for example, the porosity level of the as-printed magnetic samples is very sensitive to both powder characteristics and processing parameters. In the case of Nd-Fe-B bonded magnets, the main target is to increase the magnetic texture values once magnetically anisotropic powders are commercially available. On the other hand, for the Sm-Fe-N magnetic system, the goal is adequate powder morphology, which is mostly found as flake particles, not suitable for AM processes. In this work, the influence of processing parameters and technological properties of the raw materials employed on the final magnetic properties of the as-printed components obtained via LPBF are discussed. Densification of Nd-Fe-B bonded magnets has been reported by the feedstock composition adequation, tunning the fraction of binder. This approach allowed the obtention of bonded magnets with only 5% porosity using spherical particles. Concerning texturization methods, there are promising alternatives but still needs further investigation. In the case of Sm-Fe-N bonded magnets, adjustments on both particle morphology and feedstock composition emerge as future alternatives to reduce the current elevated porosity degree of the as-printed magnetic samples.
Keywords
Laser powder bed fusion, Rare Earths Bonded Magnets, Nd-Fe-B, Sm-Fe-N, Magnetic Properties
