Compositional clustering in Nd{sub 2}Fe{sub 14}B melt-spun ribbons

Journal Article · Mon May 01 04:00:00 EDT 2000 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.373142· OSTI ID:20216206

Lewis, L H ^[1]; Kramer, M J ^[2]; Dennis, K W ^[2]; McCallum, R W ^[2]

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1. Department of Applied Science, Materials and Chemical Sciences Division, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)
2. Ames Laboratory and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

Elevated-temperature superconducting quantum interference device magnetometry was employed to investigate the detailed phase constitution of nominally glassy stoichiometric Nd{sub 2}Fe{sub 14}B melt-spun ribbons modified with 6 wt % Ti/C and subjected to various degrees of quenching by circumferential wheel speed variations of 40, 35, and 20 m/s. While previous microstructural characterization indicated that these materials were completely amorphous, ac susceptibility and magnetization measurements analyzed within the framework of superparamagnetism indicates that the materials actually contain a concentration of crystalline phase clusters of Nd{sub 2}Fe{sub 14}B and {alpha}-Fe that remained undetected by previous microstructural characterization due to their small size (diameter <5 nm) and inhomogeneous spatial distribution. The Curie temperatures of the glassy component increase with decreasing wheel speed, while the amount of glass varies in a systematic manner from 78 to 91 wt %. The remaining phases in the quenched product are Nd{sub 2}Fe{sub 14}B and {alpha}-Fe. Analysis of the distribution and size of the {alpha}-Fe clusters provides insight into the nucleation and growth process that ultimately produces the crystallized microstructure associated with high energy-product melt-spun Nd{sub 2}Fe{sub 14}B-based magnets. (c) 2000 American Institute of Physics.

• OSTI ID: 20216206
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 87; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
BORON ALLOYS
CURIE POINT
EXPERIMENTAL DATA
IRON ALLOYS
MAGNETIZATION
NEODYMIUM ALLOYS
PERMANENT MAGNETS
SOLIDIFICATION
SPIN-ON COATINGS