Evaluation of sintered and reground Nd-Fe-B alloys with Co, Dy and Al substitutions for use in bonded magnets

Journal Article · Mon Apr 15 04:00:00 EDT 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.347979· OSTI ID:5564253

Li, M; Strnat, K J ^[1]; Mildrum, H F ^[2]

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1. KJS Associates, 1712 Springfield Street, Dayton, Ohio 45403 (USA)
2. University of Dayton, Dayton, Ohio 45469 (USA)

Crushing sintered Nd-Fe-B into coarse powders quickly destroys their coercivity and alignability in a magnetic field, making them useless for bonded magnets. But a double anneal of 890 {degree}C/1 h plus 570 {degree}C/1 h can largely restore these properties for particles {gt}200 {mu}m. Alloys modified with two or more of Co, Dy, and Al additions suffer much lower {ital H}{sub {ital ci}} and {ital H}{sub {ital k}} losses during grinding. They also respond favorably to annealing, but less than the ternary alloy. Sintered magnets of four compositions were prepared in many size fractions between {similar to}50 and 1600 {mu}m and demagnetization curves measured as-crushed, after single and double anneals. Powders of alloys (Nd{sub 0.88}Dy{sub 0.12})(Fe{sub 0.8{minus}{ital x}}Co{sub 0.12}B{sub 0.08} Al{sub {ital x}}){sub 5.5}, where {ital x}=0.012 and 0.036, retain {ital H}{sub {ital ci}} values above 10 kOe down to {similar to}200 {mu}m and could be quite useful in bonded magnet fabrication. This paper reports detailed results for two selected compositions: the six-component alloy with {ital x}=0.012 and ternary Nd-Fe-B.

• OSTI ID: 5564253
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:8; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
ANNEALING
BONDING
BORON ALLOYS
COBALT ADDITIONS
COBALT ALLOYS
COERCIVE FORCE
COMMINUTION
CRUSHING
DYSPROSIUM ADDITIONS
DYSPROSIUM ALLOYS
FABRICATION
HEAT TREATMENTS
IRON ALLOYS
JOINING
MAGNETIC PROPERTIES
MAGNETS
METALLURGY
NEODYMIUM ALLOYS
PHYSICAL PROPERTIES
POWDER METALLURGY
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
SINTERING