ESTONIAN ACADEMY
PUBLISHERS
eesti teaduste
akadeemia kirjastus
PUBLISHED
SINCE 1952
 
Proceeding cover
proceedings
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2020): 1.045

Fabrication and microstructural analysis of didymium–iron–boron magnet alloys with cerium additions; pp. 166–171

Full article in PDF format | doi: 10.3176/proc.2016.2.02

Authors
Zorjana Mural, Märt Kolnes, Hosein Afshari, Lauri Kollo, Joosep Link, Renno Veinthal

Abstract

A common industrially accepted method for producing magnetic alloys with fine, α-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 106 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 105 K/s, rare earth-rich phase content about 4%, thickness of dendrites 1.1 μm, arm spacing of dendrites 0.35 μm, 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 x 103 K/s completely prevented the formation of the undesired features in the microstructure of the cast.


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