Material Engineering of 3D-Printed Silicon Steel Alloys for the Next Generation of Electrical Machines and Sustainable Electromobility

Recently, there has been a growing need for sustainable and efficient electromobility. Also, the interest in highly-flexible resource-saving production has been increasing. To this aim, standardized manufacturing of electrified powertrains is being replaced by scalable production solutions. With this being said, additive manufacturing (AM) technology through its unmatched flexibility, can be used to manufacture the next generation of electrical machines. One of the main challenges of the existing electrical machines is that the stator and rotor are manufactured only using 2D electrical steel laminations without any design freedom for the third dimension. This research is targeting 3D printing of high quality magnetic materials. Multiple AM technologies allow industrialization of unconventional solutions and different chemical compositions of magnetic material powders can be customized for a wide range of applications including transportation electrification. This study is focusing on 3D micro extrusion technology of highly viscous silicon steel (FeSi) powder pastes. Different soft magnetic cores are printed with different silicon contents. The magnetic BH characteristics and losses of the cores are measured and compared and the best Si content with a higher limitation for eddy current losses is identified. Finally, advanced shape-profiled cores are printed and characterized to evaluate their magnetic properties in comparison to the standard electrical steel. The findings indicate that the utilization of a 3D printed core successfully mitigates eddy current losses within the high-frequency range, while also offering the added benefit of constructing intricate structures.