Development of a “top-down” production route for Nd-Fe-B magnets
Permanent magnetic materials play an increasingly important role for technologies in the fields of energy generation, mobility, as well as in automation and entertainment industry. The production of permanent magnets has taken a strong upturn in the last decade, and the demand for magnets has increased dramatically due to the increasing automation, as well as the change from combustion engines to electro mobility.
Due to their high magnetic energy density, the neodymium-iron-boron (Nd-Fe-B) alloys are among the most important permanent magnet materials. However, this alloy is permanent-magnetic only if it has a specific microstructure (e.g. uniform grain size and grain boundary for decoupling of the grains). The conventional Nd-Fe-B magnets production nowadays takes place via a powder metallurgical route through sintering, which is a complex manufacturing process and associated with high costs in the value added.
Goal of the Pioneer Fund Project
In the project “New top-down synthesis methods” of the LOEWE RESPONSE project at the TU Darmstadt, a forming process route was developed and patented by the departments PtU, PhM and FM starting from Nd-Fe-B castings. The goal of this process route is a cheap and efficient production of Nd-Fe-B permanent magnets compared to the classical powder route by means of a continuous forming process. The previous results have demonstrated the high potential of this process route by achieving significant magnetic hardening (increase in remanence and coercivity).
The goal of the Pioneer Fund project is the validation of this process for further implementation in industrial production. The manufacturing process for permanent magnets offers varied advantages compared with the conventional sintering process, such as a lower number of manufacturing steps, higher efficiency as well as lower energy consumption and so on. If the achieved magnetic properties are comparable to those of commercial sintered magnets, the state-of-the-art sintering process for permanent magnets can be replaced in some areas by the continuous top-down approach.
Involved departments and institutes
The Institute for Produktionstechnik und Umformmaschinen (PtU), lead by Prof. Dr.-Ing Dipl.-Wirtsch.-Ing. Peter Groche, deals with teaching and research in the field of production and forming technology.
The Department of Physical Metallurgy (PhM) lead by Prof. Dr.-Ing. Karsten Durst from the Department of Materials Science deals with the structure-property correlations of metallic materials, layers and glasses.
The Department of Functional Materials (FM) under the direction of Prof. Dr. Oliver Gutfleisch also from the Department of Materials Science deals with the topics of high-performance permanent magnets for electric mobility and energy technology and magnetic cooling.