Rare-Earth-Free Iron-Nickel-based ordered phases for permanent magnet applications

Permanent magnets (PMs) are crucial components in many modern technologies and have gained a prominent role in energy applications, as they allow the conversion of mechanical work into electricity and vice versa. Currently, the best performing PMs are based on rare-earth (RE) containing phases. But the commercial production of RE-PMs suffers a few serious drawbacks. Since the early 2000s, the source of rare-earths has been geographically concentrated in China, which has imposed strict export quotas and taxes. This has caused a steep increase of the price of RE and severely affected the supply chain of PM raw materials, the so-called rare-earth crisis. Due to the limited availability and high volatility in price, REs are considered by the EU critical raw materials and there has been an increasing need to develop high performance magnets with no (or very limited) rare-earth elements. Tetrataenite, an ordered intermetallic ferromagnetic compound composed of readily available Fe and Ni, has recently been considered the most promising material for substituting REs in permanent magnet applications. In nature, tetrataenite has been found only in meteorites and its synthesis is extremely challenging. REFINE’s ambition is to accomplish a clear progress beyond the state-of-the-art within the laboratory production of ordered Fe-Ni-based phases. Mechanical activation processes, such as mechanical alloying, cryomilling and cold rolling, are used to enhance short-range atomic rearrangements and provide a drive towards chemical ordering and improved magnetic performances. Ultimately, REFINE's objective is to develop and produce a next-generation high-performing rare-earth-free magnetic material for permanent magnet applications, containing low-cost, abundant, non-critical raw elements. The core activities are part of the work plan for a PhD student, who has started working in December 2021. The main experimental tasks carried out in 2022 included the pre-alloy production by mechanical alloying and arc melting, followed by mechanical activation by cryomilling. Selected samples were structurally characterized at the Swiss Norwegian Beamline at the ESRF in Grenoble. The first annealing experiments to obtain the tetrataenite phase have begun in the second half of 2022 and a first batch of samples will be sent by the end of the year to our R&D partner IMDEA (Spain) for magnetic characterization. A first batch of pre-alloys produced by our R&D partner IPSAS (Slovakia) will also be delivered by the end of the year for subsequent mechanical processing at IFE.

REFINE's goal is to develop and produce a next-generation high-performing rare-earth-free magnetic material for permanent magnet applications, containing low-cost abundant elements and no critical raw elements. It will address the synthesis of the ordered L10 FeNi phase (tetrataenite), which in nature is found only in some meteorites, by systematically exploring the use of mechanical activation processing and by employing established structural, microstructural and magnetic characterization protocols to outline structure-property relationship in materials tetrataenite-containing materials. REFINE addresses the needs for providing new permanent magnets for smaller, lighter and more energy efficient electric devices, and accelerating the transition from fossil fuels to renewable energy sources and adoption of zero-emission transport modes. In addition to the low-cost of the constituent elements, processing and manufacturing conditions considered in this proposal fulfill the requirements of scalability, eco-efficiency and cost-effective implementation.