Iron-rich amorphous materials built via laser powder bed fusion target stator and rotor efficiency in small electric drives, in research undertaken at Saarland University

The alloys reduce remagnetization losses by eliminating the crystalline microstructure that is responsible for internal friction and heat build-up in conventional soft-magnetic materials.

The focus of the Saarland team’s work centered on the replacement of coarse-grained crystalline iron alloys, which are used in stators and rotors with metallic glasses containing 70% to 80% iron.

“We are looking into ways of cutting these efficiency losses by improving the materials used in electric motors,” stated Professor Ralf Busch. “In today’s motors, the stator and rotor components are made from conventional soft magnetic, coarse-grained iron alloys. 

“Although these alloys are already optimized, they still exhibit relatively high hysteresis losses during re-magnetization. We want to replace these conventional crystalline alloys with amorphous, glass-like alloys, as they lose hardly any energy during re-magnetization.”

In conventional motors, losses rise as magnetic fields repeatedly reverse and force microscopic magnetic domains to reorient within a crystal lattice. This generates the aforementioned hysteresis losses – an excessive loss of energy.

By contrast, the absence of crystallites in the amorphous materials allows those magnetic regions to reorient more freely, and this reduces iron losses and heat generation.

“The losses decrease dramatically when the crystallites are extremely small, i.e. nanocrystalline in structure, or when the crystal structure is absent altogether, i.e. the material is glass-like or amorphous,” added Busch.

The team identified three alloy compositions that resist crystallization while meeting the requirements for additive manufacturing and motor use. The materials are processed by LPBF, in which layers of approximately 50 micrometers form fully amorphous motor parts. 

Potential applications range across e-scooters, drones, and other small electric vehicles and devices, which could benefit from notable improvements in efficiency.

“The challenge now is to develop the process so that it works reliably in practice and at an industrial scale,” concluded Professor Matthias Nienhaus.

The work was conducted under the AM2SoftMag project, which received funding of €3.5 million ($4m) through the European Innovation Council’s Horizon Europe Pathfinder Open program.

*This article originally appeared on [Joseph Caron-Dawe]. [VoxelMatters] is the original author of this piece