Project title: Novel Permanent Magnets based on Ce₂(FeCo)₁₄B/Fe₆₅Co₃₅ Core Shell Nanoparticles

Project Acronym: NanoMagShell

Project code: PN-III-P2-2.1-PED-2019-2054

Contract No.: 316PED/2020

Project Director: Dr. Marian Grigoras
E-mail: mgrigoras@phys-iasi.ro
Tel: +40 232 430680
Fax: +40 232 231132

Project Funding: 520,000.00 RON

Funding Agency: Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI)

Project Duration: 03/08/2020-31/03/2022 (20 months)

Project Summary:

The permanent magnets (PMs) have become vital components used in advanced electronics systems, military applications, robotics and emerging green energy technologies like the hybrid electric vehicle (HEV) and wind turbines. The strongest and most used PMs available today are based on Nd-Fe-B type alloys with additions of heavy rare earth Dy, Pr, Tb etc. However, these heavy rare earths have becomes materials of risk and therefore, there is a strong need to find and produce new permanent magnets without heavy rare earths, but with functional performance as good as possible.

The aim of this project is to explore the development of a new type of permanent magnets based on core-shell-type (CeFeCoB/FeCo) nanopowders, PMs able to develop magnetic performance in order to fill the gap between energy product of ferrites and NdFeB magnets based on critical rare earths. The motivation of this choice start, from: (i) the fact that (Ce), is more abundant, and the quantitatively is 4 times more than Nd and Pr taken together, and (ii) our good preliminary results obtained on CeFeCoB ribbons, (iii) our skills to produce nanopowders by cryo-milling technique. The idea is to envelop Ce-FeCo-B as individual nanoparticles with FeCo soft phase, in order to ensure maximum exchange coupling and after that to turn them into PMs with desired properties by spark plasma sintering technique.  

Project team:

The research team consists of the Project Director - Dr. Grigoras Marian, five experienced Senior Scientists - Prof. Dr. Horia Chiriac, Dr. Nicoleta Lupu, Dr. Lostun Mihaela, Dr. Dumitru Daniel Herea and Dr. George Stoian, and two experienced research technicians- Ms. Marieta Porcescu and Ms. Carmen Nuțu.

Main Objective of the Project

The objectiv of the project, is  to  increase  the  TRL  level  of  existing  Ce-FeCo-B  ribbons  by  develop  a new type  of  permanent  magnets  based  on  “core-shell” type  (CeFeCoB/FeCo)  nanopowders, capable  of  being used as substitutes for permanent magnets based on critical rare earths elements, with a suitable magnetic performance in order to fill the gap between energy product of ferrites (5.5 MGOe) and NdFeB magnets (35 MGOe).

Specific Objectives of the Project

Processing of Ce₂(FeCo)₁₄B ribbons with nanocrystalline structure by cryo-miling technique and physical characterization of resulted nanopowders; establishing the optimal parameters of the cryo-milling. 

Obtaining of core-shell structure for Ce₂(FeCo)₁₄B nanoparticles by controlled coating with Fe₆₅Co₃₅ by chemical reduction.

Development of permanent magnets by SPS technique; Establishing and optimization of compaction factors / alignment (time, pressure, temperature, magnetic field)

Testing and validation of the demonstration model consisting in PMs, by a detailed investigation of magnetic properties and performances.

Expected results:

• 4 articles sent to ISI-ranked journals;
• 3 presentations of the project results at well-known international conferences on the topics of the project;
• 1 patent application;
• 3 new types of materials / products.

Achieved results (corresponding to the stages completed in the period 3.08.2019-31.03.2022):

 Publications:

1. M. Grigoras, M. Lostun, G. Stoian, N. Lupu, F. Borza, “High performance MM–FeCo–B spark plasma sintered magnets with nonmagnetic grain-boundary phase” Intermetallics, 135 (2021) 107232. https://doi.org/10.1016/j.intermet.2021.107232
2. M. Grigoras, M. Lostun, F. Borza, M. Porcescu, N. Lupu, “The effect of the Mo addition on the magnetic properties and phase constituents of the Ce-(FeCo)–B ribbons” Intermetallics, 141 (2022) 107425. https://doi.org/10.1016/j.intermet.2021.107425
3. Marian Grigoras, Mihaela Lostun, Firuta Borza, Marieta Porcescu, George Stoian and Nicoleta Lupu, “Microstructure and magnetic properties of Ce₁₄Fe₇₈Co₂B₆ nanopowders prepared by ball milling at low temperature” Magnetochemistry, 160 7 (2021). https://doi.org/10.3390/magnetochemistry7120160
4. Tiberiu Roman_, Nicoleta Lupu, Iulian-Ioan Murgulescu, Gabriel Ababei, George Stoian, Mihaela Lostun, Marieta Porcescu, Marian Grigoras, “Facile method of raising the LTP content in MnBi alloys using sequential separation techniques for Bi and Mn: issues and how to overcome them”  Acta Materialia, in evaluation, March 2022.
5. Mihaela Lostun, Firuta Borza, Nicoleta Lupu, Gabriel Ababei, George Stoian, Marieta Porcescu, Marian Grigoras, “The effect of dry and wet milling on microstructure and magnetic properties of CeFeB powder” Journal of Magnetism and Magnetic Materials, in evaluation, March 2022.

Conference presentations:

1. INTERMAG 2021, Lyon, France, APRIL 26-30, 2021 “Characterization and Magnetic Properties of Ce-FeCo-B Nanoparticles Prepared by Cryo-Milling” M. Grigoras, M. Lostun , G. Stoian, H. Chiriac and N. Lupu;
2. 13th International Conference on Physics of Advanced Materials (ICPAM-13), Sant Feliu de Guixols, Spain, September 24-30, 2021 “Improvement of magnetic properties for Mo doped Ce-Fe-B ribbons” M. Grigoras, M. Lostun , D. D. Herea, G. Stoian, H. Chiriac and N. Lupu;
3. 13th International Conference on Physics of Advanced Materials (ICPAM-13), Sant Feliu de Guixols, Spain, September 24-30, 2021, “Fe-Cr-Nb-B glassy powders obtained by high-energy ball milling of amorphous alloy ribbons”, M. Lostun, M. Grigoras, G. Stoian, G. Ababei, M. Porcescu, H. Chiriac and N. Lupu.

Products:

• Nanopowders based on Ce₂(FeCo)₁₄B phase with nanocrystalline structure and optimized composition;
• Ce₂(FeCo)₁₄B/Fe₆₅Co₃₅ core-shell-type nanopowders;
• Permanent magnets based on Ce₂(FeCo)₁₄B/Fe₆₅Co₃₅ core-shell-type nanoparticles.

Reports:

2020 Activity Report Summary (in Romanian)
2021 Activity Report Summary (in Romanian)
2022 Activity Report Summary (in Romanian)
Final report summary (in Romanian)