Soft Magnetic Materials

Soft magnetic materials with low core losses and high power density are essential for next-generation electric drives, power electronics and energy-efficient mobility systems. At Fraunhofer IFAM, we develop and process advanced soft magnetic components using innovative powder metallurgical technologies that go far beyond conventional manufacturing routes.

Our near-net-shape manufacturing strategies enable the production of soft magnetic components with application-specific property profiles, optimized for frequency range and thermal stability. In addition, powder metallurgy allows broad material flexibility and the integration of functional features directly into the component design.

Powder Metallurgical Manufacturing of Soft Magnetic Components

Additive Screen Printing of Electrical Steel Laminations

Additive Screen Printing enables the near-net-shape fabrication of electrical steel laminations with tailored alloy composition and thickness.

Reducing the sheet thickness (d < 200 µm) and increasing the silicon content (e.g. Fe-6.5Si) significantly decreases eddy current losses, particularly at higher frequencies. This enables highly efficient stator and rotor designs for electric drives.

Furthermore, multimaterial screen printing allows the fabrication of electrical steel stacks.

© Fraunhofer IFAM Dresden
Iron losses at 1 T vs. frequency (Fe-6.5Si)

Nanocrystalline Components by FAST/SPS

Amorphous ribbons are consolidated into nanocrystalline soft magnetic components using FAST (Field Assisted Sintering Technology) / SPS (Spark Plasma Sintering).

The high heating rates enable precise microstructure control and the processing of so-called “high B” alloys. Nanocrystalline materials with magnetic inductions above 1.2 T can be achieved, exceeding conventional alloy performance.

This technology enables:

Adjustable magnetic properties
Higher saturation induction than conventional nanocrystalline cores
Compact and complex geometries

Nanocrystalline Components by FAST/SPS — © Fraunhofer IFAM Dresden
Hysteresis loops of wounded toroids made of Vitroperm and Nanomet compacted in the FASTS/SPS and images and cross sections of b) Nanomet flake cores and c) compacted wounded toroids.

Soft Magnetic Composites

Isotropic soft magnetic composites are produced by pressing electrically insulated soft magnetic powders. Magnetic properties can be tuned by powder particle size and composition depending on the desired application.

Characterization of Soft Magnetic Materials and Components

A comprehensive characterization strategy ensures reliable material performance and application-specific optimization.

Magnetic characterization

Magnetic properties are determined by measuring B-H curves on ribbons or toroidal cores under AC and DC fields (B-H analyzers, LCR Meter). Frequency-dependent losses can be evaluated up to 1 MHz. This includes loss separation and measurement of characteristic loss curves.

Microstructural and Powder Characterization

Microstructural investigations are performed using light microscopy and scanning electron microscopy (SEM) to correlate functional properties with microstructure.

Comprehensive powder characterization in our accredited laboratory includes:

Particle size distribution
Morphology
Impurity analysis

This enables systematic optimization from powder to final component.

Dr. Inge Lindemann's “Soft Magnetic Materials” working group researches the powder metallurgical production of application-relevant material concepts for the manufacture of loss-optimized soft magnetic components. In the “Powder Metallurgy” department, the group has comprehensive expertise and the latest powder processing technologies, which also take generative manufacturing into account. The fields of application range from modern energy converters in electrical machines and power electronics.

The project "WeiMag" (600420) is funded internally through the Fraunhofer Attract program.