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Nano Research & Applications
ISSN 2471-9838
E u r o S c i C o n C o n f e r e n c e o n
Nanotechnology &
Smart Materials
O c t o b e r 0 4 - 0 6 , 2 0 1 8
Am s t e r d a m , N e t h e r l a n d s
Nanotechnology & Smart Materials 2018
New processing of RE-based magnetic materials
Spomenka Kobe, Marko Soderžnik, Kristina Žagar and
Jean-Marie Dubois
Jožef Stefan Institute, Slovenia
R
are-earth transition metals permanent magnets are vital components in the rapidly-developing renewable energy sector, where
the motors require strong magnets with the ability to operate at temperatures well over 100 °C. To achieve high coercivity,
remanence and consequently high energy product at elevated temperatures, the addition of heavy rare earth (HRE) to the basic
Nd-Fe-B composition is needed. On the list of critical raw materials published by the EC in 2014, HRE is on the very top of it. To
drastically reduce the use of HRE, we focused on developing a new method, which should enable us to achieve the properties
needed for high-temperature application with the lowest amount of scarce elements. With our new inventive technique, further
transferred to pilot production, we could minimize the amount of HRE used, down to 0.2 at %, the improvement of coercivity was
30 % with minimal loss in remanence. The total saving of the HRE is 16-times less need of HRE for the same performance, which
is a significant contribution to the world economy and clean environment. In studying the mechanism for such an improvement
in coercivity without significantly decreasing the remanence, a detailed microstructure investigation was performed by using
high-resolution transmission electron microscopy. The so-called core-shell grains were observed, the thickness of the shell varied
from 150 to 200 nm. By using the electron holography imaging, we also observe the magnetic domains. Reconstructed phase
showed the magnetic flux distribution and colour maps. The contour spacing was π/2. Besides the use of these newly developed
high energy magnets for electric and hybrid cars and the wind turbine generators the important application is also as the source
of the magnetic field in the development of the new magnetic cooling devices.
spomenka.kobe@ijs.siNano Res Appl Volume:4
DOI: 10.21767/2471-9838-C6-025