Ferrite-based magnets to power future green economy
The EU-funded AMPHIBIAN project successfully developed a patented flywheel – a mechanical device designed to efficiently store energy – as well as permanent magnetic material produced without rare-earth minerals. “We hope that, thanks to our results, ferrite-metallic nanowire composites are brought forward as a powerful candidate to substitute rare-earth materials,” says project coordinator Adrián Quesada from the Spanish National Research Council. “More generally, given the many green advantages of using ferrites, we hope that our overall strategy of improving ferrite magnets is given more attention in the future.” Since project completion in December 2019, the AMPHIBIAN consortium has been collaborating with a United Kingdom-based company in order to develop the first ferrite-based and rare-earth-free wind turbine generator. “The potential here is huge because wind turbines usually require tons of rare-earths to operate,” explains Quesada. “We are also looking at substituting rare-earth car components with our nanowire composites.”
An essential everyday material
A permanent magnet is a material that can spontaneously create a magnetic field by itself, without the need to pass a current through it. This unique property makes them very useful for everyday applications such as speakers and microphones as well as hard drives and sensors. “Mechanical energy can be transformed into electrical energy and vice versa,” adds Quesada. “This is why permanent magnets are used in generators and motors. As we transition towards a greener future, demand for magnets to generate energy in wind turbines and electric car motors will dramatically increase." Demand for permanent magnets has however created challenges. The best magnets contain rare-earth minerals, and sourcing these elements involves cost, supply chain and environmental issues. “These minerals fall within the category of what we call critical raw materials,” says Quesada. “There is a clear need to find alternatives that could substitute rare-earths, especially in certain applications that require only moderate performance. This would help us to reduce our dependency on critical materials.”
Sustainable power for the future
The key objective of the AMPHIBIAN project was to improve the properties of magnets based on ferrites, and to then demonstrate their efficacy in energy storage devices called flywheels. “We chose ferrites as our main material as this material is readily available, way more environmentally friendly and cheap,” adds Quesada. The team, made up of materials scientists, physicists, theorists, chemists and engineers, began by identifying optimal particle sizes, shapes and arrangements to improve overall properties of the novel magnets. Initial tests indicated that particle sizes needed to be much smaller than expected, obliging the team to use nanoscale particles. “These were much more difficult to produce in large amounts,” says Quesada. “However, we overcame this problem by refocusing our efforts and resources towards the production of nanostructures and by working with smaller prototypes.” The end result is a novel flywheel that operates at a greatly reduced magnetic field, as well as a composite magnet based on ferrites and metallic nanowires. “These fulfil the goals we had in terms of performance improvement,” says Quesada. “The novel flywheel is expected to be commercialised by 2022, and both results have been patented.” In addition, magnetic tiles for bathrooms and kitchens, fabricated out of recycled ferrite powders, have been developed, along with a software package for simulating the properties and particle rotation of magnetic composites. The commercialisation of both products is also underway.
Keywords
AMPHIBIAN, minerals, metallic, sustainable, wind turbine, energy, flywheel, magnetic, nanowire, ferrite, car
