Fabrication and microstructural analysis of didymium–iron–boron magnet alloys with cerium additions

A common industrially accepted method for producing magnetic alloys with fine, alpha -iron-free microstructure is strip casting. Small amounts of alloys can be rapidly solidified with the method called splat quenching. In both cases the quenching rate can reach 10 super( 6) K/s. This work reports th...

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Bibliographic Details
Published in:Proceedings of the Estonian Academy of Sciences 2016-01, Vol.65 (2), p.166-166
Main Authors: Mural, Zorjana, Kolnes, Maert, Afshari, Hosein, Kollo, Lauri, Link, Joosep, Veinthal, Renno
Format: Article
Language:English
Subjects:
Alloys
Boron
Cerium
Cooling rate
Dendrites
Dendritic structure
Fabrication
Magnetic alloys
Microstructure
Oxygen content
Quenching
Quenching (cooling)
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Summary:A common industrially accepted method for producing magnetic alloys with fine, alpha -iron-free microstructure is strip casting. Small amounts of alloys can be rapidly solidified with the method called splat quenching. In both cases the quenching rate can reach 10 super( 6) K/s. This work reports the results of using a method for producing small amounts of NdFeB magnetic alloys with Ce additions. The aim of the study was to determine the influence of the cooling rate on the microstructure of the cast. Implementing centrifugal casting in vacuum resulted in NdFeB alloys with the following optimal parameters: sample thickness 0.3 mm, cooling rate 10 super( 5) K/s, rare earth-rich phase content about 4%, thickness of dendrites 1.1 mu m, arm spacing of dendrites 0.35 mu m, and oxygen content not more than 650 ppm. Theoretically, it is possible to increase the alloy thickness up to 2 mm. Decreasing the cooling speed to the critical level 4 10 super( 3) K/s completely prevented the formation of the undesired features in the microstructure of the cast.
ISSN:1736-6046
1736-7530
DOI:10.3176/proc.2016.2.02