TY - JOUR

T1 - Production of Permanent Magnets from Recycled NdFeB Powder with Powder Extrusion Moulding

AU - Rathfelder, Stefan

AU - Schuschnigg, Stephan

AU - Kukla, Christian

AU - Holzer, Clemens

AU - Burkhardt, Carlo

PY - 2024/4/18

Y1 - 2024/4/18

N2 - In the last fifteen years, several groups have investigated metal injection moulding (MIM) of NdFeB powder to produce isotropic or anisotropic rare earth magnets of greater geometric complexity than that achieved by the conventional pressing and sintering approach. However, due to the powder’s high affinity for oxygen and carbon uptake, sufficient remanence and coercivity remains difficult. This article presents a novel approach to producing NdFeB magnets from recycled material using Powder Extrusion Moulding (PEM) in a continuous process. The process route uses powder obtained from recycling rare earth magnets through Hydrogen Processing of Magnetic Scrap (HPMS). This article presents the results of tailored powder processing, the production of mouldable feedstock based on a special binder system, and moulding with PEM to produce green and sintered parts. The magnetic properties and microstructures of debinded and sintered samples are presented and discussed, focusing on the influence of filling ratio and challenging processing conditions on interstitial content as well as density and magnetic properties.

AB - In the last fifteen years, several groups have investigated metal injection moulding (MIM) of NdFeB powder to produce isotropic or anisotropic rare earth magnets of greater geometric complexity than that achieved by the conventional pressing and sintering approach. However, due to the powder’s high affinity for oxygen and carbon uptake, sufficient remanence and coercivity remains difficult. This article presents a novel approach to producing NdFeB magnets from recycled material using Powder Extrusion Moulding (PEM) in a continuous process. The process route uses powder obtained from recycling rare earth magnets through Hydrogen Processing of Magnetic Scrap (HPMS). This article presents the results of tailored powder processing, the production of mouldable feedstock based on a special binder system, and moulding with PEM to produce green and sintered parts. The magnetic properties and microstructures of debinded and sintered samples are presented and discussed, focusing on the influence of filling ratio and challenging processing conditions on interstitial content as well as density and magnetic properties.

KW - powder extrusion moulding (PEM

KW - metal injection moulding (MIM)

KW - production of NdFeB permanent magnets

KW - recycling of EOL-magnets

U2 - 10.3390/jmmp8020081

DO - 10.3390/jmmp8020081

M3 - Article

VL - 8.2024

JO - Journal of Manufacturing and Materials Processing

JF - Journal of Manufacturing and Materials Processing

SN - 2504-4494

IS - 2

M1 - 81

ER -