Resource-conserving permanent magnets with high Ce content for sustainable energy converters

• Applicant: Professorin Dr. Dagmar Goll
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554685675

There is a large gap between weak, inexpensive, sustainable hard ferrite permanent magnets and the strong, expensive, less sustainable FeNdB rare earth magnets. On a laboratory scale, it has recently been experimentally proven that FeNdB sintered magnets, in which 50-75% of the typically required amount of Nd/neodymium is substituted by the more readily available and less expensive elements Ce/Cer and La/Lanthanum, can meet the performance requirements for use in an electric motor. For example, for sintered magnets Fe70.9-(CexNd1-x)18.8-B5.8-M4.5 (at%; M = Co, Ti, Al, Ga, Cu; x = 0.5) at room temperature, a coercive field of µ0Hc = 1.29 T, a remanence of Jr = 1.02 T and a maximum energy product of (BH)max = 176.5 kJ/m3 (x = 0.75: µ0Hc = 0.72 T, Jr = 0.80 T, (BH)max = 114.5 kJ/m3) were achieved. They therefore have potential to close the gap between hard ferrites and FeNdB magnets. The additional use of La allows targeted adjustment of the magnetic parameters and improvement of their temperature stability. The aim of the AMACE project is the realization of high-performance magnet prototypes with high Ce substitution levels (based on the laboratory magnets Ce50%/75%) and application-relevant properties under application-related conditions (substantive objective) as well as the testing of upscaling and recyclability including possible recycling options (strategic objective). In particular, the aim is to transfer existing findings for FeNdB to Ce-containing sintered magnets and to research and evaluate potential improvements in terms of composition, process adaptation and aging behavior. These questions, which are essential for the potential commercialization of sintered magnets with a high cerium content, were not addressed in the preliminary work, especially with regard to current and future sustainability requirements on the part of the legislator. The work to be carried out for this purpose is based on the following overarching hypothesis: Compared to magnets with no or little Ce, FeNdB sintered magnets with a high Ce content require specially adapted alloy and process technology due to specific differences in terms of the phases that occur, their proportions and compositions as well as their thermodynamic behavior. Through systematic and knowledge-based optimization, the properties achieved to date can be further improved and larger quantities or sintered magnets can be reproducibly produced. AMACE is a knowledge transfer project within the framework of DFG Transfer HAW/FH PLUS. The work program provides for the joint processing of the project content together with two application partners (industrial companies Siemens AG and GKN Powder Metallurgy GmbH) in order to transfer scientific findings and results of basic research into application and to provide new impulses for basic scientific research. The results of AMACE are in the pre-competitive area.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: GKN Powder Metallurgy Engineering GmbH; Siemens AG ; Standort Erlangen