Evolution and degradation of magnetic MnBi phase

2018 ◽  
Author(s):  
Irena Janotová ◽  
Peter Švec ◽  
Igor Maťko ◽  
Dušan Janičkovič ◽  
Peter Švec Sr.
Keyword(s):  
Mnbi Phase

Influence of Gravity Driven Convection on the Directional Solidification of Bi/MnBi Eutectic Composites

1981 ◽  
Vol 9 ◽  
Author(s):  
Ron G. Pirich ◽  
D.J. Larson
Keyword(s):  
Directional Solidification ◽  
Normal Gravity ◽  
Volume Fraction ◽  
Sounding Rocket ◽  
Low Gravity ◽  
Gravity Driven ◽  
Morphological Differences ◽  
Mnbi Phase ◽  
Irregular Interface

ABSTRACTThe role of gravity on Bridgman-Stockharger directional solidification of eutectic Bi/MnBi has been studied in reduced gravity aboard NASA sounding rocket SPAR flight experiments and contrasted with normal gravity investigations. The directional solidification of eutectic Ri/MnBi results in a low volume fraction, faceted/nonfaceted aligned rod eutectic whose MnRi rod size, interrod spacing, thermal and magnetic properties are sensitive functions of solidification processing conditions. The morphology of the low-gravity samples showed striking differences compared with identically processed,normal gravity samples grown in the same apparatus. The MnBi rod diameter and interrod spacing distributions were significantly smaller, approximately 50%, for the lowgravity samples compared with identically processed one gravity samples. Accompanying the smaller MnBi rod diameters observed in the flight samples, was an increase in permanent magnet properties which reached greater than 97% of the theoretical maximum.Gravitationally induced thermal instabilities in one-gravity which result in irregular interface movement and associated difficulty of the faceted MnBi phase to branch are suggested to explain the morphological differences between one and low gravity solidification.

scholarly journals Preparation of highly pure α-MnBi phase via melt-spinning

AIP Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 056702 ◽  
Author(s):  
A. M. Gabay ◽  
G. C. Hadjipanayis ◽  
J. Cui
Keyword(s):  
Melt Spinning ◽  
Mnbi Phase

Magnetic-field-induced enhancement for synthesizing ferromagnetic MnBi phase by solid-state reaction sintering

2014 ◽  
Vol 615 ◽  
pp. 131-134 ◽  
Author(s):  
Yoshifuru Mitsui ◽  
Rie Y. Umetsu ◽  
Keiichi Koyama ◽  
Kazuo Watanabe
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Solid State Reaction ◽  
Reaction Sintering ◽  
Mnbi Phase
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