Additive manufacturing of iron components for magnetic shielding

Researchers in the Gu Research Group and SUPER lab have developed an additive manufacturing method for making iron-based magnetic shielding coatings and components by controlling the geometry of the iron, leading to significantly better performance. Magnetic shielding protects vulnerable devices used in automotives, aerospace and aviation, telecommunications, data storage, medical imaging equipment, high precision instruments, and more. Permeability, magnetic saturation, thermal stability, and operating frequency range determine magnetic shield effectiveness. Iron has excellent magnetic saturation and thermal stability, but can only be used in the frequency range of 100 Hz due to eddy current losses. Fe-Si and other soft metal alloys are typically used, which are expensive and difficult to process.

The Stanford researchers' additive manufacturing (AM) method leverages space-filling curves to increase the iron components frequency range three orders of magnitude to above 1 kHz, without affecting iron's saturation, permeability, or thermal stability. The process is easier, faster, and less expensive than industry standards, and resulting prototypes meet or outperform industry standard devices made from more resistive nanocrystalline and amorphous compositions, and laminate devices made from electrical steel. (See graph) In addition, the AM shield shape can conform closely to the shape of the component it is shielding, and other high-saturation and high temperature shielding materials may be used, such as FeNi and FeCo alloys.

Stage of Development – Proof of Concept
Topology optimization is ongoing for iron, other magnetic metallic alloys (FeNi and FeCo), and amorphous metals to increase their cut-off frequency to the MHz regime to compete with ferrites and Iron/Polymer composites.