Quantitative characterization of additional ferromagnetic phase in melt-quenched and sintered Nd{endash}Fe{endash}B-based magnets

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.362295· OSTI ID:280063

Lewis, L H; Welch, D O ^[1]; Pourarian, F ^[2]

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1. Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973 (United States)
2. Carnegie Mellon Research Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania 15230-2950 (United States)

Quantitative evidence of a ferromagnetic Fe-rich minor phase present in both melt-quenched/die-upset and sintered magnets based on the Nd{sub 2}Fe{sub 14}B composition is presented. Full hysteresis loops were obtained at elevated temperatures (650 K{le}{ital T}{le}800 K) and were subsequently decomposed to obtain the saturation magnetization {ital M}{sub {ital s}} of the minor phase as well as the paramagnetic slope of the 2-14-1 major phase as a function of temperature. Assuming a composition of pure iron, the calculated volume {percent} of the impurity phase in the die-upset magnets is consistent with that obtained from previous observations of the widths and geometry of the intergranular phase found in the same magnets. The magnetization of the ferromagnetic impurity phase in the melt-quenched magnets decreases more rapidly than that of pure iron; extrapolation indicates a Curie temperature in the range 925 K{le}{ital T}{le}975 K. The paramagnetic susceptibility of the Nd{sub 2}Fe{sub 14}B main phases exhibits Curie{endash}Weiss behavior with the same paramagnetic Curie temperature for both sintered and die-upset samples. The Curie constants differ, however, probably due to the different degrees of crystallographic alignment. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Brookhaven National Laboratory
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 280063
• Report Number(s): CONF-951101--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IMPURITIES
IRON BORIDES
MAGNETIC MATERIALS
MAGNETIC PROPERTIES
NEODYMIUM BORIDES
PERMANENT MAGNETS
PHASE STUDIES
RAPID SOLIDIFICATION
SINTERED MATERIALS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K