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Recycling of soft magnetic composites

Jörgensen, Evelina LU (2025) KASM10 20242
Centre for Analysis and Synthesis
Abstract
Electrification of the automotive industry calls for high performing electric engines.
Since the use of iron from primary sources in the production of engine cores has a
high environmental impact, it would be beneficial if they could be made mostly from
recycled materials. Soft magnetic composites used as cores in electric engines have
lower mechanical strength compared to the alternatives. This is sometimes described
as an advantage from a recycling point of view, however, the subject of recycling
soft magnetic composites and its effect on the material properties has not yet been
thoroughly researched. This study aims to investigate the possibility of recycling soft
magnetic composites while preserving the properties of... (More)
Electrification of the automotive industry calls for high performing electric engines.
Since the use of iron from primary sources in the production of engine cores has a
high environmental impact, it would be beneficial if they could be made mostly from
recycled materials. Soft magnetic composites used as cores in electric engines have
lower mechanical strength compared to the alternatives. This is sometimes described
as an advantage from a recycling point of view, however, the subject of recycling
soft magnetic composites and its effect on the material properties has not yet been
thoroughly researched. This study aims to investigate the possibility of recycling soft
magnetic composites while preserving the properties of the material. In this report,
soft magnetic composite materials are crushed with a spiked roller followed by a disk
mill or a jaw crusher. The effect crushing had on the material was analysed with FTIR,
SEM and EDS. Magnetic and mechanical properties were also measured with Vickers
hardness testing, TRS and hysteresis measurement. Actions were taken on the crushed
powders to improve the magnetic properties of the final components such as adding
additional coating, annealing them in nitrogen, hydrogen and argon, as well as mixing
them with virgin powder. Crushing the materials yielded powders with damaged
coating, increased hardness and a high amount of impurities. The components made
from the recycled powders had high core losses as a result. It was concluded that a
more aggressive crushing paired with a thick additional coating to the crushed powders
resulted in components with promising low core losses. Annealing experiments showed
that hydrogen was the most effective atmosphere, decreasing the amount of impurities
drastically. The low amount of impurities resulted in particle surfaces more susceptible
to an additional coating. This, along with the reduced coercivity achieved also due
to the lower amount of impurities had the effect of lowering the core losses of the
final component. The best performing material measured was a material crushed at
high speed, annealed in hydrogen and with a thick additional coating. To produce
this material, there is no need for primary iron as raw material, melting or water
atomization. The reduction in carbon dioxide equivalent emissions from the removal
of primary iron and the two initial process steps were estimated to around 60% (Less)
Please use this url to cite or link to this publication:
author
Jörgensen, Evelina LU
supervisor
organization
course
KASM10 20242
year
type
H2 - Master's Degree (Two Years)
subject
keywords
materials chemistry, recycling, soft magnetic composites, material development, sustainability
language
English
id
9187363
date added to LUP
2025-04-10 08:25:10
date last changed
2025-04-10 08:25:10
@misc{9187363,
  abstract     = {{Electrification of the automotive industry calls for high performing electric engines.
 Since the use of iron from primary sources in the production of engine cores has a
 high environmental impact, it would be beneficial if they could be made mostly from
 recycled materials. Soft magnetic composites used as cores in electric engines have
 lower mechanical strength compared to the alternatives. This is sometimes described
 as an advantage from a recycling point of view, however, the subject of recycling
 soft magnetic composites and its effect on the material properties has not yet been
 thoroughly researched. This study aims to investigate the possibility of recycling soft
 magnetic composites while preserving the properties of the material. In this report,
 soft magnetic composite materials are crushed with a spiked roller followed by a disk
 mill or a jaw crusher. The effect crushing had on the material was analysed with FTIR,
 SEM and EDS. Magnetic and mechanical properties were also measured with Vickers
 hardness testing, TRS and hysteresis measurement. Actions were taken on the crushed
 powders to improve the magnetic properties of the final components such as adding
 additional coating, annealing them in nitrogen, hydrogen and argon, as well as mixing
 them with virgin powder. Crushing the materials yielded powders with damaged
 coating, increased hardness and a high amount of impurities. The components made
 from the recycled powders had high core losses as a result. It was concluded that a
 more aggressive crushing paired with a thick additional coating to the crushed powders
 resulted in components with promising low core losses. Annealing experiments showed
 that hydrogen was the most effective atmosphere, decreasing the amount of impurities
 drastically. The low amount of impurities resulted in particle surfaces more susceptible
 to an additional coating. This, along with the reduced coercivity achieved also due
 to the lower amount of impurities had the effect of lowering the core losses of the
 final component. The best performing material measured was a material crushed at
 high speed, annealed in hydrogen and with a thick additional coating. To produce
 this material, there is no need for primary iron as raw material, melting or water
 atomization. The reduction in carbon dioxide equivalent emissions from the removal
 of primary iron and the two initial process steps were estimated to around 60%}},
  author       = {{Jörgensen, Evelina}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Recycling of soft magnetic composites}},
  year         = {{2025}},
}