Magnetic properties of Mn substituted Nd–Fe–B composite

Xie, Guangyuan; Xu, Jianhong; Lin, Pinghua; Lu, M.; Du, Youwei; Zhou, Yuan

doi:10.1016/j.jmmm.2003.11.379

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…[103][104][105] Cobalt addition also preserves high J r and i H c values (at least up to 0?20 of Co substitution). [106][107][108][109] In contrast to Co, Mn substitution for Fe reduces T c but for concentrations below 1?5 at-%, results in higher coercivity values (up to 400 kA m 21 in composite materials with 9 at-%Nd). 106,107 Small Cr additions (up to 0?4 at-%) appear to induce finer mean grain sizes and thus, enhanced (BH) max values but with the drawback of lower T c values.…”

Section: Transition Metal Replacementsmentioning

confidence: 99%

“…[106][107][108][109] In contrast to Co, Mn substitution for Fe reduces T c but for concentrations below 1?5 at-%, results in higher coercivity values (up to 400 kA m 21 in composite materials with 9 at-%Nd). 106,107 Small Cr additions (up to 0?4 at-%) appear to induce finer mean grain sizes and thus, enhanced (BH) max values but with the drawback of lower T c values. 108 For an RE concentration of 5?5 at-%, 109 higher Cr contents (3-10 at-%) lead to i H c increments from 502 to 590 kA m 21 , together with marked reductions in J r (from 0?9 to 0?71 T).…”

Section: Transition Metal Replacementsmentioning

confidence: 99%

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Exchange coupled nanocomposite hard magnetic alloys

Betancourt

Davies

2010

Materials Science and Technology

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The processing, structures and phase constitutions and the magnetic properties of nanocomposite hard magnetic alloys are reviewed. The emphasis is on rare earth (RE)–iron–boron alloys in which the hard magnetic phase RE2Fe14B is intermixed with one or more soft magnetic phases. Processing–structure–property relationships are the principal focus, in particular, the role of the hard and soft nanocrystallite dimensions in promoting intergrain ferromagnetic exchange coupling and the consequent enhancement of remanent magnetisation and the technologically important maximum energy density. The powder processing, chill block melt spinning, mechanical alloying and thin film deposition routes to develop nanocrystalline and nanocomposite structures are reviewed. The coercivity mechanism in ultrafine grained alloys and the influence of crystallite dimensions are discussed, as are the effects on intrinsic and extrinsic properties of RE substitutions, replacement of iron by other transition metals and enrichment of the boron content. Exchange enhancements in Sm–Co based nanocomposite bulk alloys and in nanoscale FePt/ α-Fe composite thin films are briefly considered, together with thin film materials involving exchange coupling between ferromagnetic and antiferromagnetic phases, in core–shell type structures of transition metal compounds surrounded by oxides and in mechanically alloyed materials. The processing and magnetic properties of bonded magnets based on nanocrystalline/nanocomposite REFeB alloys are discussed. The possibility of producing anisotropic hard/soft composites with properties approaching the theoretical maximum is considered and the extent to which this goal has been realised for fully dense alloys identified.

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Section: Transition Metal Replacementsmentioning

confidence: 99%

Section: Transition Metal Replacementsmentioning

confidence: 99%

Exchange coupled nanocomposite hard magnetic alloys

Betancourt

Davies

2010

Materials Science and Technology

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“…When the temperature reaches 580 ∘ C, the alloy with additional elements has no crystallization. The contrary crystallization phenomenon of improving crystallization tendency of the Mn substitution in Nd 2 Fe 14 B/ -Fe nanocomposites was also observed by Xie et al [13].…”

Section: Methodsmentioning

confidence: 72%

Improvement of the Magnetic Properties of Nanocrystalline Nd_12.3(FeZrNbCu)_81.7B_6.0 Alloys with Dy Substitutions

Yang

Guo

et al. 2015

Journal of Nanomaterials

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Nd12.3−xDyxFe81.7Zr0.8Nb0.8Cu0.4B6.0 (x=0–2.5)ribbons have been prepared by melt-spun at 30 m/s and subsequent annealing. The influence of addition of Dy on the crystallization behavior, magnetic properties, and microstructure were investigated. Differential scanning calorimeter (DSC) and X-ray diffraction (XRD) revealed a single-phase material. Microstructure studies using transmission electron microscopy (TEM) had shown a significant microstructure refinement with Dy addition. Wohlfarth’s analysis showed that the exchange coupling interactions increased first with Dy contentxincreasing, reached the maximum value atx=0.5, and then slightly decreased withxfurther increasing. Optimal magnetic properties withJr=1.09 T,Hci=1048 kA/m, andBHmax=169.5 kJ/m3are achieved by annealing the melt-spun ribbons withx=0.5at% at 700°C for 10 min.

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“…Recently, investigations have been carried out on Nd-Fe-B nanocomposites doped with Cr and it was found that Cr addition increases the intrinsic coercivity but reduces the magnetization [3][4][5][6]. Substitution of a small amount of Mn for Fe promotes crystallization and enhances both the coercivity and the remanence ratio [7,8]. The exchange coupling between ferromagnetic and AFM materials has been extensively studied in thin-film systems [9][10][11], in transition-metal particles embedded in their oxides [12][13][14] and in mechanically alloyed powders [15,16].…”

Section: Introductionmentioning

confidence: 99%