Bulk rare earth free permanent magnets

Introduction

Permanent magnets are essential components of an enormous amount of consumer and industrial products. Their production rises annually, especially due to their use in fast-growing green technologies such as electric mobility.

Material Systems

High-performance magnets with a large energy product are usually based on the NdFeB material system. The major components are rare-earth elements, which are listed as critical materials.

Novel Approaches

Novel permanent magnets use the concept of magnetic coupling effects. In the course of the ERC Starting Grant SPDTuM, we have developed a new processing route to synthesize permanent magnets based on this concept.

Objective

The objective of this ERC PoC Grant is to use this processing route and apply it to the MnBi system, which represents a rare-earth free alternative to the currently used NdFeB magnets.

Benefits of MnBi

As an additional benefit, the magnetic -MnBi phase exhibits an increasing coercivity with rising temperature. Thus, magnets based on MnBi will be especially well-suited for high-temperature applications.

Processing Method

We use high-pressure torsion, a severe plastic deformation method, for processing, which has the advantage that the key -MnBi phase can be directly formed during processing. Coupled to a soft magnetic phase, a high-performance permanent magnet with an excellent energy product will be obtained.

Current Limitations

So far, this type of magnet has only been successfully obtained in limited volumes (thin films, powders).

Up-scaling Potential

With our processing route, it is possible to synthesize magnets in dimensions with about 100,000 times larger volume. The novel MnBi permanent magnets will be characterized with state-of-the-art methods in terms of their microstructure and magnetic properties.

Evaluation and Commercialization

The up-scaling potential of the developed processes from laboratory to industrial conditions will be further critically evaluated. These activities will be complemented by patent protection to facilitate commercialization and outreach to potential industry partners for the introduction of our novel method and new collaborations.