NEXMAG project has managed to cover successfully scientific research and technological development in the field of rare earth-free permanent magnets. In addition to scientific highlights achieved on the MnAl system, a patent focused on a functional prototype has been filled, and the world-leading manufacturer of metal powders –Höganäs AB (Sweden)– has established an on-going industrial collaboration for implementation and up-scaling of some of NEXMAG’s results.
Permanent magnets (PMs) are a crucial element in several high-tech markets such as energy and transport sectors, medical technologies and a broad range of electronic products. In addition, PMs play a very important role in efforts focused on an increased use of low carbon technologies to ensure a high living standard. However, most of nowadays-technological PMs contain critical raw materials (rare-earths) as fundamental constituents and EU does not own the natural resources, which might result in a future bottleneck to the supply-chain.
NEXMAG (http://www.nexmag.net) has focused on the development of PM properties in Mn-based alloys: MnAl and MnBi. MnAl is an interesting PM candidate based on excellent theoretically predicted PM properties, low-density, low-cost and abundance of Mn and Al, together with good mechanical properties. MnBi offers excellent PM properties at high temperatures mainly intended for specific low-volume applications demanding high-magnetic performance under those conditions.
Highlights of the project can be summarized as follows:
- Development of PM properties in gas-atomized MnAl particles by nanostructuration with unprecedented short milling times by application of an “ultrafast-milling” method. Milling times extremely short of 30 – 270 s (vs 20-30 h typically reported) have been successfully used.
- Tuning microstructure and phase transformation by ultrafast-milling and cryomilling followed by a single-annealing step makes possible to go from a multiphase phase to a ferromagnetic single-phase MnAl system, with customized PM properties. This has been proven on bulk alloy, gas-atomized particles and melt-spun ribbons.
- Establishment of the correlation between morphological, microstructural and magnetic properties, which allows the development of high-coercive (above 5 kOe) isotropic nanocrystalline MnAl powder.
- Development of particulate and continuous MnBi thin films with a coercivity of 29 kOe at 500 K, counting among the largest reported ones for the MnBi system.
- Production of MnAl/metal nanocomposites with enhanced magnetization by matching complimentary properties of dissimilar materials.
These achievements have led to results of relevance from both scientific and technological points of view:
Invitation by the EU Commission to share its stand at the EuroScience Open Forum (ESOF)-2016 held in Manchester. A prototype using MnAl material was presented to the assistants.
Filled Patent (Ref. EP16382224):
“System to obtain three-dimensional information from the magnetic field generated by an external permanent magnet source with applications in: detection of structural instabilities in civil engineering, advanced security ID cards and biomedical applications”.
Impact on EU industrial leadership:
The results obtained in NEXMAG have led to an industrial project with the company Höganäs AB (Sweden) interested in exploitation of the results. This projects focuses on application of the ultrafast-milling method to gas-atomized MnAl-based particles for the up-scaled production of a new generation of rare earth-free permanent magnet material.
- J. Rial, M. Villanueva, E. Céspedes, N. Lopez, J. Camarero, L. Marshall, L.H. Lewis and A. Bollero, “Application of a novel flash-milling procedure for coercivity development in nanocrystalline MnAl magnet powders”, J. Phys. D: Appl. Phys. 50, 105004 (2017).
- J. Y. Law, J. Rial, M. Villanueva, N. López, J. Camarero, L. G. Marshall, J. S. Blázquez, J. M. Borrego, V. Franco, A. Conde, L. H. Lewis and A. Bollero, “Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles”, J Alloys Compd. 712, 373 (2017).
- E. Céspedes, M. Villanueva, C. Navío, F. J. Mompeán, M. García-Hernández, A. Inchausti, P. Pedraz, M. R. Osorio, J. Camarero and A. Bollero, “High coercive LTP-MnBi for high temperature applications: from isolated particles to film-like structures”, J. Alloys Compd. 729, 1156 (2017).
- I. Janotová, P. Švec Sr., P. Švec, I. Matʼko, D. Janičkovič, J. Zigo, M. Mihalkovič, J. Marcin and I. Škorvánek, “Phase analysis and structure of rapidly quenched Al-Mn systems”, J. Alloys Compd. 707, 137 (2017).
|Call Topic||Materials for Sustainable and Affordable Low Carbon Energy Technologies|
|Duration in months||36|
|Total project cost||865,333 €|
C/ Faraday 9, 28049 Madrid, SpainProf. Alberto Bollero
Phone: +34 91 299 8758
|Link to ERA-LEARN||View on ERA-LEARN website|