Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 46: Poster II
MA 46.34: Poster
Thursday, March 21, 2024, 15:00–18:00, Poster C
Two-powder method for heavy rare earth reduced sintered NdFeB magnets — •Abdullatif Durgun1, Konrad Opelt2, Chi-Chia Lin2, Jürgen Gassmann2, Imants Dirba1, and Oliver Gutfleisch1 — 1TU Darmstadt, Department of Materials and Geosciences, Functional Materials, 64287 Darmstadt, Germany — 2Fraunhofer IWKS, 63457 Hanau, Germany
Nd2Fe14B magnets play crucial role in e-motor technology, enhancing efficiency and power density. However, their use in high-temperature motors (up to 200 °C) is limited due to the low Curie temperature and decreased coercivity. As a result, NdFeB magnets require high coercivity (*2400 kA/m) at room temperature for effective operation in high-temperature e-motor applications. This can be achieved by replacing Nd atoms with heavy rare earths like Dy or Tb, however with significantly increased costs and reduced magnetization. Therefore, this study aims to improve the thermal stability and coercivity of sintered NdFeB magnets by forming (Nd,Dy/Tb)2Fe14B-rich shells around the Nd2Fe14B grains. Sintered NdFeB magnets were fabricated via our patented 2-powder-method [1,2] using NdFeB main phase and Dy/Tb-rich high-anisotropy powders. The impact of powder particle size, alloy composition and mixing ratios is systematically investigated to optimize the magnet microstructure and magnetic properties. Forming (Nd,Dy/Tb)2Fe14B shells around the NdFeB core boosts coercivity without significant magnetization loss, enabling the use of cost-and-resource-efficient and large volume NdFeB magnets at high temperatures.
Keywords: Nd-Fe-B; Permanent magnet; Criticality; Grain Boundary Engineering; Recycling