Nanocrystallinity and magnetic property enhancement in melt-spun iron-rare earth-base hard magnetic alloys

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of Materials Engineering and Performance; (United States)

DOI:https://doi.org/10.1007/BF02661744· OSTI ID:5361559

Davies, H A; Manaf, A; Zhang, P Z ^[1]

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1. Univ. of Sheffield (United Kingdom). Dept. of Engineering Materials

Refinement of the grain size below [approximately]35 nm mean diameter in melt-spun FeNdB-base alloys leads to enhancement of remanent polarization, J[sub r], above the level predicted by the Stoner-Wohlfarth theory for an aggregate of independent, randomly oriented, and uniaxial magnetic particles. This article summarizes the results of the recent systematic research on this phenomenon, including the influence of alloy composition and processing conditions on the crystallite size, degree of enhancement of J[sub r], and maximum energy product (BH)[sub max]. It has been shown that the effect can also occur in ternary FeNdB alloys, without the addition of silicon or aluminum, which was originally thought necessary, providing the nanocrystallites are not magnetically decoupled by a paramagnetic second phase. Values of (BH)[sub max] above 160 kJ. m[sup [minus]3] have been achieved. The relationship between grain size, J[sub r], intrinsic coercivity, [sub J]H[sub c], and (BH)[sub max] are discussed in terms of magnetic exchange coupling, anisotropy, and other parameters. Recent extension of this work to the enhancement of properties in Fe-Mischmental-Boron-base alloys and to bonded magnets with a nanocrystalline structure is also described.

• OSTI ID: 5361559
• Journal Information: Journal of Materials Engineering and Performance; (United States), Vol. 2:4; ISSN 1059-9495
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
MAGNETIC PROPERTIES
IRON BASE ALLOYS
NEODYMIUM ALLOYS
CHEMICAL COMPOSITION
EXPERIMENTAL DATA
GRAIN REFINEMENT
PERMANENT MAGNETS
ALLOYS
DATA
INFORMATION
IRON ALLOYS
MAGNETS
NUMERICAL DATA
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
360104* - Metals & Alloys- Physical Properties