Magnetic materials are important in the production, transmission and use of electrical energy. It has become obvious over the years that an increased use of low carbon technologies is necessary to ensure a high living standard. Permanent magnets (PMs), used in multitude of technological applications, play a very important role in these efforts. Many nowadays applications traditionally use rare earth (RE)-based PMs, as no relevant problems in terms of availability or high and unstable pricing raised at the time of their implementation. The situation has dramatically changed in recent years due to an increased monopoly.
This increased need of PMs in combination with the strategically geographical situation of REs make mandatory, first, an efficient and well focused use of these elements for specific purposes (high performing applications or micro-scalable devices) and, additionally, a reinforcement in the search of PMs alternatives in applications areas where the use of REs may be reduced or totally avoided.
We work actively in collaboration with international research centers and companies in the search of improved and novel permanent magnet materials. Our research is based on three main pillars:
- Development of basic research and its translation to industry and end-users.
- Up-scalability of the procedures to avoid that achieved advances stop at the laboratory.
- Sustainability through recycling and efficient use of the resources.
Figure 1. Permanent magnets (PMs) in nowadays-technological applications: from energy generation, going through energy transformation and to devices. [Image: IMDEA Nanoscience]
RE-free PMs, constituted by non-critical elements would contribute to solve the EU dependency of REs and would revert the situation of the PMs from the nowadays situation which is determined by the geographical distribution of the raw materials to a new market where the know-how and technological development will determine the market leader.
The Group of Permanent Magnets and Applications works in close cooperation with recognized international research centres [Northeastern University Boston (USA), IFE (Norway), IPSAS (Slovakia)…] and well-established companies [Höganäs AB (Sweden), IMA S.L. (Spain)…] in the search of alternatives to RE-PMs and of more efficient and environmentally friendly synthesis and processing routes for PMs.
Advanced 3D-printing technology is used by the Group for printing rare earth-free and hybrid Neo/ferrite PMs. Laser-assisted additive manufacturing, typically used for 3D-printing of metallic alloys, is not a feasible option for PMs due to the high temperatures achieved during processing. Thermally controlled 3D-printing makes use of PM/polymer composite filament to print magnetic elements. This approach intends to change the actual technological paradigm based on design of devices according to magnets with predefined geometries (in-catalogue), which lately limits their efficiency.
Figure 2. Coercivity development in nanocrystalline MnAl particles achieved by the innovative rapid-milling procedure (30-270 s) followed by reduced-temperature annealing (365ºC/10min). Published in J. Phys. D: Appl. Phys. 50, 105004 (2017).
Figure 3. Synthesis of metallic alloys by gas-atomization and preparation of the metallic/polymer composite by the solution casting method.
Figure 4. 3D-printer used for high-density materials (PMs and metallic alloys). Photograph of metallic/polymer composite (filling factor: 80 wt%) and filament. 3D printed elements (hexagonal columns) prepared from the filament.
Figure 5. First-time fabrication of permanent magnet filament of MnAlC (extensible to different alloys) and 3D-printed magnetic piece with complex structure. More information at Sci. Technol. Adv. Mater., 19 (1), 465-473 (2018).
Figure 6. Precursor materials for the synthesis of ferrites and fabricated magnets (prototypes and large) from ferrite powder with permanent magnet properties.
Figure 7. Recycling of ferrite residues in a manufactory plant. The quality of the recycled ferrite powder has been tested and compared to that of the new starting ferrite material. The magnetic properties of the recycled powder not only match those of the starting material acquired by the company for the production of magnets but exceed them. A coercivity value 3.5 times larger than that of the new starting ferrite powder, accompanied by a 25% increase in remanence, makes this material a new and improved ferrite product to re-enter the production chain in the factory with an extended applications range. Extended information: ACS Sustainable Chem. Eng. 5, 3243 (2017)
Figure 8. SEM image of Sr-ferrite sintered magnet prepared at IMA S.L. [Image: IMDEA Nanoscience]
Figure 9. Scooter with an electric ferrite-based motor designed and constructed in the frame of EU- FP7 NANOPYME.