The metal injection moulding (MIM) of NdFeB powder to produce rare earth magnets with high geometrical complexity is a promising route in order to avoid machining waste, saving precious raw materials and to enable new applications. However, difficult process ability, due to the high affinity of the powder to oxygen and carbon pickup, requires a carefully modified MIM approach: The REProMag (Resource Efficient Production of Magnets) processing route is based on the use of powder obtained from recycling of used rare earth magnets by the hydrogen decrepitation (HD) process. A proprietary binder system has been developed for producing a mouldable MIM feedstock, having a chemical composition optimised for the processing of the highly reactive magnetic powder. The processing steps and their challenges with respect to processing parameters on interstitial contents and magnetic properties of isotropic sintered MIM parts (with and without Nd additions) are presented and discussed.
REProMag is funded by EU's HORIZON2020FoF2, GA 636881