High coercivity, high energy product Nd-Fe-B magnets with less or no dysprosium

High performance motors, like those in hybrid electric vehicles, use high performance Nd-Fe-B magnets that contain up to 12 wt% of dysprosium (Dy) in order to increase the coercivity, and avoid demagnetization at elevated temperatures. However, the global rare earth elements (Nd, Dy, etc) supply chain risk combined with predicted supply shortages for dysprosium which DOE has deemed critical has become a grave concern for the healthy development of all green technologies operating with permanent magnets. Recently, efforts have been directed towards new designs of permanent magnet motors which allow the use of lower energy product magnets, or the use of induction motors; however, they have resulted in lower performances compared to rare earth permanent magnet motors, and will have critical implementation problems. The proposed project will develop a methodology for the production of high-performance, high- coercivity Nd-Fe-B permanent magnets with less or no dysprosium, based on (i) control of Dy atoms distribution at grain boundaries through a newly discovered phenomenon beyond the current research on grain boundary diffusion concept, in order to minimize their usage in Nd- Dy-Fe-B magnets and (ii) microstructure engineering aimed at grain size refinement and new methods for intergranular phase control in Dy-free Nd-Fe-B magnets. The proposed technologies will demonstrate 30% higher coercivity values for magnets with Dy contents equivalent to those of their current commercial counterparts (i.e., the new Dy-free magnets will have 30% higher coercivity than existing ones). Correspondingly, the amount of Dy needed to reach a higher level of coercivity will be decreased by 30% in the new Dy-lean Nd-Fe-B magnets. Moreover, a reduced or eliminated Dy content will lead to a higher maximum energy product for these magnets throughout their entire operating temperature range. The cost of the magnets to be developed with the proposed technologies is expected to be reduced substantially compared to the price of the current commercial counterparts with the same level of coercivity.