Ferromagnetic grain boundary signature in die-upset RE-Fe-B magnets

Journal Article · Fri Dec 01 04:00:00 EST 1995 · Scripta Metallurgica et Materialia

DOI:https://doi.org/10.1016/0956-716X(95)00410-W· OSTI ID:131463

Lewis, L H; Zhu, Y; Welch, D O ^[1]

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1. Brookhaven National Lab., Upton, NY (United States). Materials Science Division

Previous nanostructural and nanocompositional studies performed on the boundaries of deformed grains in two die-upset rare earth magnets with bulk compositions Nd{sub 13.75}fe{sub 80.25}B{sub 6} and Pr{sub 13.75}Fe{sub 80.25}B{sub 6} indicate that the intergranular phase in many grain boundaries is enriched in iron relative to the bulk. The authors present here preliminary magnetic data that provide further evidence that this grain boundary phase is indeed iron-rich, and in fact appears to be ferromagnetic. Hysteresis loops were performed at 800 K on die-upset magnets with the above compositions. Each sample showed a clear hysteresis with coercivities between 34 and 40 Oe and an average remanence 4{pi}B{sub R} of 6.8 G for the Nd-based sample and 10.3 G for the Pr-based sample. The ferromagnetic signals measured at high temperature in these magnets are attributed to the iron-rich grain boundary phase. The implications of this conclusion with respect to coercivity are discussed.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 131463
• Journal Information: Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 10-11 Vol. 33; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COERCIVE FORCE
FERROMAGNETISM
GRAIN BOUNDARIES
HYSTERESIS
IRON BORIDES
MAGNETIC PROPERTIES
MICROSTRUCTURE
NEODYMIUM BORIDES
PRASEODYMIUM BORIDES
TEMPERATURE DEPENDENCE