scholarly journals High-Throughput Screening of Rare-Earth-Lean Intermetallic 1-13-X Compounds for Good Hard-Magnetic Properties

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1096 ◽  
Author(s):  
Georg Krugel ◽  
Wolfgang Körner ◽  
Daniel F. Urban ◽  
Oliver Gutfleisch ◽  
Christian Elsässer
Keyword(s):  
Rare Earth ◽  
High Throughput ◽  
High Throughput Screening ◽  
Spontaneous Magnetization ◽  
Anisotropy Field ◽  
Structure Type ◽  
Anisotropy Constant ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product

By computational high-throughput screening, the spontaneous magnetization M s , uniaxial magnetocrystalline anisotropy constant K 1 , anisotropy field H a , and maximum energy product ( B H ) max are estimated for ferromagnetic intermetallic phases with a tetragonal 1-13-X structure related to the LaCo 9 Si 4 structure type. For SmFe 13 N, a ( B H ) max as high as that of Nd 2 Fe 14 B and a comparable K 1 are predicted. Further promising candidates of composition SmFe 12 AN with A = Co, Ni, Cu, Zn, Ga, Ti, V, Al, Si, or P are identified which potentially reach (BH) max values higher than 400 kJ/m 3 combined with significant K 1 values, while containing almost 50% less rare-earth atoms than Nd 2 Fe 14 B.

Microstructure Of Fe-Nd-B Alloys Tailored To Approach Theoretical Coercrvtty Limits

1999 ◽  
Vol 5 (S2) ◽  
pp. 26-27
Author(s):  
Kannan M. Krishnan ◽  
Er. Girt ◽  
E. C. Nelson ◽  
G. Thomas ◽  
Ferdinand Hofer
Keyword(s):  
Magnetic Particles ◽  
Permanent Magnets ◽  
Spontaneous Magnetization ◽  
Particle Interaction ◽  
Maximum Energy ◽  
Interacting Particles ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Oriented Samples ◽  
The Difference

Performance of permanent magnets for a variety of applications is often determined by the maximum energy product (BH)max. In order to obtain high (BH)max permanent magnetic materials have to have large coercivity. In theory the coercive field of ideally oriented, non-interacting, single domain, magnetic particles, assuming Kl is much bigger than K2, was shown to be He = 2K1/Ms - N Ms, where Kl and K2 are the magnetocrystalline anisotropy constants, Ms is the spontaneous magnetization and N is the demagnetization factor. For randomly oriented non-interacting particles the Stoner-Wohlfarth model predicts that the value of Hc decreases to about half. However, experimentally obtained values of the coercitive fields in permanent magnets are 3 to 10 and 2 times smaller for well oriented and randomly oriented samples, respectively. This discrepancy was attributed to inter-particle interaction and the microstructure of the permanent magnets. In order to understand the difference between the theoretically predicted and experimentally obtained results for He we prepared rapidly quenched, Nd-rich, NdxFe14B (2 < x < 150) ribbons.

Microstructure of high-energy product Fe-Nd-B magnequench ribbons

1986 ◽  
Vol 44 ◽  
pp. 826-827
Author(s):  
Y. L. Chen
Keyword(s):  
Anisotropy Field ◽  
Microstructural Characterization ◽  
High Energy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
High Anisotropy ◽  
Energy Products ◽  
Very High

Melt-spun Fe-Nd-B MAGNEQUENCH® ribbons have been produced by Croat et al. with energy products in excess of 10 MG.Oe using a relatively narrow window of composition and quenching speed. The hard magnetic phase has subsequently been identified as the Nd2Fe14B compound which has a very high anisotropy field. The microstructure of the MAGNEQUENCH® ribbon which has a maximum energy product of 14.1 MG•0e was found to consist of equiaxed Nd2Fe14B grains surrounded by a very thin intergranular film. This paper presents the results of some of our earlv work on the microstructural characterization of high energy product MAGNEQUENCH® ribbons having nominal compositions of Nd13Fe82.6B4.4 and Nd15Fe79.9B5.1. The purpose of this investigation was to characterize the microstructures of various MAGNEQUENCH® ribbons for correlation with their magnetic properties.

scholarly journals Coercive force mechanism in Nd-Fe-B nanocrystalline magnet investigated by SANS

2014 ◽  
Vol 70 (a1) ◽  
pp. C146-C146
Author(s):  
Tetsuro Ueno ◽  
Kotaro Saito ◽  
Masao Yano ◽  
Masashi Harada ◽  
Tetsuya Shoji ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
High Efficiency ◽  
Intensity Variation ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
High Maximum

Permanent magnet material with high maximum energy product is demanded for industrial applications such as high-efficiency motors for hybrid and electric vehicles. Maximum energy product depends on the coercive force and the saturation magnetization. In order to achieve the high maximum energy product, current Nd-Fe-B magnets are doped with heavy rare-earth element Dy to enhance the coercive force at the expense of reducing the saturation magnetization. Viewed from another side, a supply of Dy is highly concerned because of the inequitable distribution of rare-earth resources on the Earth. Therefore, development of a Dy-free Nd-Fe-B magnet is desired. In this context, we have fabricated the Dy-free Nd-Fe-B nanocrystalline magnet and performed the small-angle neutron scattering (SANS) experiment to reveal the mechanism of its coercive force. Hot-deformed Nd-Fe-B nanocrystalline magnets with and without the diffusion process of Pr-Cu eutectic alloy were prepared [1]. Coercive forces were 1.46 T and 2.64 T for as-deformed and Pr-Cu infiltrated sample, respectively. Magnetic field dependent SANS experiment was performed to observe the magnetization reversal process. The reversal magnetic field was swept from 0 T to 5 T. SANS intensities exhibit maxima around the coercive force for both as-deformed and infiltrated sample, which indicates the evolution of the magnetic domain structure. In addition, suppressed intensity variation in infiltrated sample compared to that in as-deformed sample indicates the magnetic isolation of Nd2Fe14B grains, which is responsible for the high coercive force. We will compare the results for Pr-Cu infiltrated sample with Nd-Cu infiltrated one [1]. This work was supported by the Elements Strategy Initiative Center for Magnetic Materials under the outsourcing project of the MEXT, Japan. We thank HZB for the allocation of neutron beamtime (Proposal No. MAT-04-2110). The sample preparation was performed under the MagHEM project.

EM of rapidly solidified permanent magnets

1992 ◽  
Vol 50 (1) ◽  
pp. 198-199
Author(s):  
Raja K. Mishra
Keyword(s):  
Melt Spinning ◽  
Permanent Magnets ◽  
Dark Field Image ◽  
Dark Field ◽  
Maximum Energy ◽  
Quench Rate ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Annular Dark Field ◽  
Rapidly Solidified

The discovery of a new class of permanent magnets based on Nd2Fe14B phase in the last decade has led to intense research and development efforts aimed at commercial exploitation of the new alloy. The material can be prepared either by rapid solidification or by powder metallurgy techniques and the resulting microstructures are very different. This paper details the microstructure of Nd-Fe-B magnets produced by melt-spinning.In melt spinning, quench rate can be varied easily by changing the rate of rotation of the quench wheel. There is an optimum quench rate when the material shows maximum magnetic hardening. For faster or slower quench rates, both coercivity and maximum energy product of the material fall off. These results can be directly related to the changes in the microstructure of the melt-spun ribbon as a function of quench rate. Figure 1 shows the microstructure of (a) an overquenched and (b) an optimally quenched ribbon. In Fig. 1(a), the material is nearly amorphous, with small nuclei of Nd2Fe14B grains visible and in Fig. 1(b) the microstructure consists of equiaxed Nd2Fe14B grains surrounded by a thin noncrystalline Nd-rich phase. Fig. 1(c) shows an annular dark field image of the intergranular phase. Nd enrichment in this phase is shown in the EDX spectra in Fig. 2.

Effects of Magnetic Powder Loading on Mechanical Properties and Magnetic Properties of Natural Rubber

2006 ◽  
Vol 45 ◽  
pp. 1423-1428
Author(s):  
Somsak Woramongconchai ◽  
Chatchawan Lohitvisat ◽  
Aree Wichainchai
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Natural Rubber ◽  
Barium Ferrite ◽  
Maximum Energy ◽  
Magnetic Powder ◽  
Elongation At Break ◽  
Maximum Energy Product ◽  
Energy Product

The effect of magnetic powders and powders loading on magnetic properties and mechanical properties of magnetic rubbers were studied. The natural rubber with magnetic powders, Barium ferrite, Neodymium iron boron, were used as starting materials to prepare magnetic rubbers. Barium ferrite (BaO.6F2O3) powders had been sintered at 1285 oC for 30 hours to improve its crystal structure. The physical properties of magnetic rubbers, residual flux density (Br), coercive force (Hc), maximum energy product (BHmax), hardness and density, had a trend to increase as enhancing magnetic powders loading. However, some properties such as, intrinsic coercive force (Hci), tensile strength and elongation at break, had a trend to decrease when the magnetic powder loading was increased. Magnetic properties of the anisotropic type, sintered powders, were higher than isotropic type, non-sintered powders, except the Hci because anisotropic magnetic rubber indicated crystal orientation in the same direction.

Replacement of NdFeB by Ferrite Magnets

2018 ◽  
Vol 912 ◽  
pp. 106-111
Author(s):  
Marcos Flavio de Campos ◽  
Daniel Rodrigues ◽  
Jose Adilson de Castro
Keyword(s):  
Wind Turbines ◽  
Maximum Energy ◽  
High Resistivity ◽  
Relevant Issue ◽  
Demagnetizing Field ◽  
Ndfeb Magnets ◽  
Electric Cars ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Proper Volume

The replacement of NdFeB magnets by ferrite magnets is discussed. For motors, remanence is relevant, implying in a volume three times that of NdFeB, when the relevant index of merit is remanence. However, if the relevant issue is the BHmax (maximum energy product), the volume for replacement should be ten times larger. The high resistivity of ferrites is a big advantage for motors. The temperature of operation is also relevant, because NdFeB magnets loss coercivity even with small increase of temperature. Different applications are discussed, as for instance, motors for electric cars and wind turbines. The choice of the proper volume depends on the evaluation of demagnetizing field in the condition of operation.

Bulk Nanocrystalline Permanent Magnets by Selective Laser Melting

2021 ◽  
Vol 58 (10) ◽  
pp. 630-643
Author(s):  
F. Trauter ◽  
J. Schanz ◽  
H. Riegel ◽  
T. Bernthaler ◽  
D. Goll ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Field Strength ◽  
Selective Laser Melting ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
Laser Melting ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Bulk Nanocrystalline ◽  
Micrometer Scale

Abstract Fe-Nd-B powders were processed by additive manufacturing using laboratory scale selective laser melting to produce bulk nanocrystalline permanent magnets. The manufacturing process was carried out in a specially developed process chamber under Ar atmosphere. This resulted in novel types of microstructures with micrometer scale clusters of nanocrystalline hard magnetic grains. Owing to this microstructure, a maximum coercive field strength (coercivity) μ0Hc of 1.16 T, a remanence Jr of 0.58 T, and a maximum energy product (BH)max of 62.3 kJ/mm3could, for example, be obtained for the composition Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8.

Effect of Dysprosium Content on the Magnetic Properties of Nanocrystalline (Pr0.25Nd0.75)10-xDyxFe82Co2B6 Alloys

2014 ◽  
Vol 789 ◽  
pp. 28-31 ◽  
Author(s):  
He Wei Ding ◽  
Chun Xiang Cui ◽  
Ji Bing Sun
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Maximum Energy ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Intrinsic Coercivity ◽  
Electronic Microscope ◽  
Microstructure And Magnetic Properties

(Pr0.25Nd0.75)10-xDyxFe82Co2B6(x=0~0.3) ribbons were prepared by melt spinning at 25m/s and subsequent annealing. The effect of Dy content on the microstructure and magnetic properties of the ribbons has been investigated by X-ray diffractometer (XRD), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). The magnetic properties related to the Dy content were characterized. Intrinsic coercivity of 598kA/m, remanence of 0.58T, and the maximum energy product (BH)max of 43kJ/m3 were achieved in (Pr0.25Nd0.75)9.8Dy0.2Fe82Co2B6 after annealing at 700°C for 10 minutes.

Enhancement of maximum energy product in exchange-coupled BaFe12O19/Fe3O4 core-shell-like nanocomposites

2019 ◽  
Vol 806 ◽  
pp. 120-126 ◽  
Author(s):  
Farzin Mohseni ◽  
Robert C. Pullar ◽  
Joaquim M. Vieira ◽  
João S. Amaral
Keyword(s):  
Maximum Energy ◽  
Core Shell ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Fe3o4 Core

Two Dimensionally Dispersed Fe/FePd Nanocomposite Particles Synthesized by Electron Beam Deposition

2005 ◽  
Vol 502 ◽  
pp. 275-280 ◽  
Author(s):  
Yoshihiko Hirotsu ◽  
Kazuhisa Sato ◽  
Junichi Kawamura
Keyword(s):  
Alloy Composition ◽  
Maximum Energy ◽  
Dual Phase ◽  
Post Deposition Annealing ◽  
Nanocomposite Particles ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Transmission Electron ◽  
Post Deposition ◽  
Beam Deposition

Isolated nanoparticles composed of bcc-Fe and L10-FePd have been fabricated by successive deposition of Pd and Fe onto NaCl substrate cleaved in air, and their structural characterization has been performed by transmission electron microscopy (TEM). Alloy composition was varied by changing the deposited Fe thickness in the thickness range between 2 and 7.5 nm with respect to the fixed Pd thickness of 1 nm. Post-deposition annealing lead to a formation of dual phase nanocomposite particles with the L10-type ordered phase and the bcc-Fe phase within each particle. The particle size little changed on annealing at 873K, indicating that both alloying and atomic ordering reactions proceeded within each nanoparticle. The size of the bcc-Fe region in Fe/FePd nanoparticles was measured from TEM images and its relation to the change of the maximum energy product was discussed.

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