Microstructure of melt spun Nd-Fe-Co-B magnets

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Acta Metallurgica; (USA)

DOI:https://doi.org/10.1016/0001-6160(89)90079-5· OSTI ID:6884686

Koestler, C; Ramesh, R; Echer, C J; Thomas, G ^[1]; Wecker, J ^[2]

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1. Dept. of Materials Science, Univ. of California, Berkeley, (CA) Mineral Engineering, Univ. of California, Berkeley, (CA) National Center for Electron Microscopy, Lawrence Berkeley Lab., Univ. of California, Berkeley, CA (US)
2. Siemens AG, Research Lab., Erlangen (DE)

In this paper the authors report results on microstructural characterization of melt spun Nd{sub 17}Fe{sub 77}B{sub 6} and Nd{sub 15}(Fe{sub 1 {minus} {ital x}}CO{sub {ital x}}){sub 77}B{sub 8} ribbons using high resolution electron microscopy, x-ray microanalysis and microdiffraction. In general, the microstructure consists of the hard magnetic Nd{sub 2}Fe{sub 14}B phase and one or more grain boundary phases. In all these materials no Nd{sub 1.1}Fe{sub 4}B{sub 4} phase was observed. The grain boundary phase in the Co-free samples appear mainly t multi-grain junctions and is a Nd-rich, crystalline (f.c.c.) phase, whereas the Co-containing specimens comprise two different f.c.c. grain boundary phases. The structural and microchemical data indicate that these are likely to be ferromagnetic and that they contain significantly less Nd than the grain boundary phase of the Co-free samples. The average matrix grain diameter is about 80 nm, but there are always some areas in every specimen where the grain diameter is very small (about 20 nm) or very large (more than 300 nm) causing differences in the size of the grain boundary phases both at the triple grain junctions and between the grains.

• OSTI ID: 6884686
• Journal Information: Acta Metallurgica; (USA), Journal Name: Acta Metallurgica; (USA) Vol. 37:7; ISSN 0001-6160; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
BORON ALLOYS
COBALT ALLOYS
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
FERROMAGNETISM
GRAIN BOUNDARIES
IRON ALLOYS
MAGNETIC PROPERTIES
MAGNETISM
MAGNETS
MICROANALYSIS
MICROSCOPY
MICROSTRUCTURE
NEODYMIUM ALLOYS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
TRANSMISSION ELECTRON MICROSCOPY