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.

scholarly journals Additive Manufacturing of Bulk Nanocrystalline FeNdB Based Permanent Magnets

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 538
Author(s):  
Dagmar Goll ◽  
Felix Trauter ◽  
Timo Bernthaler ◽  
Jochen Schanz ◽  
Harald Riegel ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
Laser Melting ◽  
Powder Bed ◽  
Melt Pool ◽  
Bulk Nanocrystalline ◽  
Ribbon Structures ◽  
Nanocrystalline Ribbon

Lab scale additive manufacturing of Fe-Nd-B based powders was performed to realize bulk nanocrystalline Fe-Nd-B based permanent magnets. For fabrication a special inert gas process chamber for laser powder bed fusion was used. Inspired by the nanocrystalline ribbon structures, well-known from melt-spinning, the concept was successfully transferred to the additive manufactured parts. For example, for Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8 (excess rare earth (RE) = Nd, Pr; the amount of additives was chosen following Magnequench (MQ) powder composition) a maximum coercivity of µ0Hc = 1.16 T, remanence Jr = 0.58 T and maximum energy density of (BH)max = 62.3 kJ/m3 have been achieved. The most important prerequisite to develop nanocrystalline printed parts with good magnetic properties is to enable rapid solidification during selective laser melting. This is made possible by a shallow melt pool during laser melting. Melt pool depths as low as 20 to 40 µm have been achieved. The printed bulk nanocrystalline Fe-Nd-B based permanent magnets have the potential to realize magnets known so far as polymer bonded magnets without polymer.

scholarly journals Additive Manufacturing of Anisotropic Sm-Fe-N Nylon Bonded Permanent Magnets

2021 ◽  
Author(s):  
Kinjal Gandha ◽  
Mariappan Paranthaman ◽  
Brian Sales ◽  
Haobo Wang ◽  
Adrian Dalagan ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Magnetic Particles ◽  
Permanent Magnets ◽  
Cost Effective ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Polyamide 12 ◽  
Energy Technologies ◽  
Energy Product ◽  
Bonded Magnet

Fabricating a bonded magnet with a near-net shape in suitable thermoplastic polymer binders is of paramount importance in the development of cost-effective energy technologies. In this work, anisotropic Sm2Fe17N3 (Sm-Fe-N) bonded magnets are additively printed using Sm-Fe-N anisotropic magnetic particles in a polymeric binder polyamide-12 (PA12). The anisotropic bonded permanent magnets are fabricated by Big Area Additive Manufacturing followed by post-aligned in a magnetic field. Optimal post-alignment results in an enhanced remanence of ~ 0.68 T in PA12 reflected in a parallel-oriented (aligned) measured direction. The maximum energy product achieved for the additively printed anisotropic bonded magnet of Sm-Fe-N in PA12 polymer is 78.8 KJ m-3. Our results show advanced processing flexibility of additive manufacturing for the development of Sm-Fe-N bonded magnets in polymer media designed for applications with no critical rare earth magnets.

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.

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.

A Comparative Study between Low and High-Energy Milling Processes for the Production of HD PrFeCoBNb Sintered Magnets

2008 ◽  
Vol 591-593 ◽  
pp. 114-119 ◽  
Author(s):  
E.A. Périgo ◽  
E.P. Soares ◽  
Hidetoshi Takiishi ◽  
C.C. Motta ◽  
Rubens Nunes de Faria Jr.
Keyword(s):  
Ball Milling ◽  
Permanent Magnets ◽  
High Energy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
High Energy Milling ◽  
Energy Product ◽  
Energy Processing ◽  
Hydrogen Decrepitation ◽  
High Degree

Roller-ball milling (RBM) or planetary ball milling (PBM) have been used together with the hydrogen decrepitation (HD) process to produce sintered permanent magnets based on a mixture of Pr16Fe76B8 and Pr14.00Fe63.90Co16.00B6.00Nb0.10 magnetic alloys. Five distinct compositions have been studied comparing low- and high-energy milling. Magnets with a particular composition and prepared using these two routes exhibited similar magnetic properties. Modifications have been carried out in the procedure of the HD stage for PBM in order to guarantee a high degree of crystallographic alignment. Pr15.00Fe69.95Co8.00B7.00Nb0.05 magnets showed the best maximum energy product for both processing routes (~ 247 kJm-3). A significant reduction in the milling time (93%) has been achieved with high-energy processing, the greatest advantage over the low-energy route.

Phase Structure and Magnetic Properties of Fe-Nb-B-Nd Type of Bulk Nanocrystalline Alloys

2013 ◽  
Vol 203-204 ◽  
pp. 302-305
Author(s):  
Grzegorz Ziółkowski ◽  
Artur Chrobak ◽  
Joanna Klimontko
Keyword(s):  
Magnetic Properties ◽  
Coercive Field ◽  
Phase Structure ◽  
Maximum Energy ◽  
Nanocrystalline Alloys ◽  
Preparation Technique ◽  
Casting Technique ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Bulk Nanocrystalline

In this work we present phase structure and magnetic properties of the (Fe80Nb6B14)1-x Ndx (x=0.08, 0.12, 0.16) bulk nanocrystalline alloys prepared by making use of mould casting technique. The applied mould allows obtaining bulk rods of 1.5 mm in diameter and about 3 cm in length. Phase structure and magnetic properties were carefully examined. It was shown that the applied preparation technique is favorable to nanocrystallization of the alloys, which was confirmed by the XRD diffraction. For all studied alloys, one can observe a formation of mainly Nd2Fe14B (hard magnetic) and Fe phases with different contributions dependently on the x parameter. It was also shown that the alloy of (Fe80Nb6B14)0.92Nd0.08 has the best hard magnetic properties with the coercive field, magnetic saturation and maximum energy product equal to 0.2 T, 117 emu/g and 13.4 kJ/m3, respectively (at room temperature). Moreover, the coercive field and maximum energy product are gradually deteriorating with increasing of rare earth addition.

NdFeB/αFe Nanocomposite Permanent Magnets with Enhanced Properties Prepared by Spark Plasma Sintering

2011 ◽  
Vol 672 ◽  
pp. 229-232
Author(s):  
Marian Grigoraş ◽  
M. Lostun ◽  
Nicoleta Lupu ◽  
Horia Chiriac
Keyword(s):  
Spark Plasma Sintering ◽  
Permanent Magnets ◽  
High Energy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Melt Spun Ribbons

Nanocomposite NdFeB/αFe magnets were obtained by spark plasma sintering technique using high energy ball-milled Nd-Fe-B melt-spun ribbons mixed in different weight ratios with Fe commercial powders. The remanence of SPS nanocomposite magnets increases with the Fe powders content from 6.1 for 4 wt.% Fe to 6.4 kG for 5 wt.% Fe, while the estimated maximum energy product is also increased from 9.0 to 10.6 MGOe.

Influence of Milling Time on Magnetic Properties and Microstructure of Sintered Nd-Fe-B Based Permanent Magnets

2018 ◽  
Vol 930 ◽  
pp. 445-448
Author(s):  
R.G.T. Fim ◽  
M.R.M. Silva ◽  
S.C. Silva ◽  
Julio Cesar Serafim Casini ◽  
P.A.P. Wendhausen ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Milling Time ◽  
Maximum Energy ◽  
Inhomogeneous Distribution ◽  
Maximum Energy Product ◽  
Grain Sizes ◽  
Energy Product

In this paper, the effect of the grain size on sintered Nd-Fe-B based permanent magnets was investigated. In order, the magnets were produced by different milling times at 200 rpm and then vacuum sintered at 1373 K for 60 minutes followed by cooling outside the furnace. The magnets either produced by lower and higher milling times (30 and 75 minutes) exhibited lower remanence and coercivity, due the inhomogeneous distribution of the grain sizes. The magnet produced by intermediary milling time (45 minutes) exhibited the highest properties among all samples, with remanence of 1.06 T, coercivity of 891.3 KA.m-1, maximum energy product of 211 KJ.m3and a squareness factor equal 0.92.

Study on the Nanostructure and Magnetic Properties of NdFeNbB Permanent Magnets

2010 ◽  
Vol 638-642 ◽  
pp. 1749-1754
Author(s):  
X.F. Wang ◽  
X.Y. Chen ◽  
Z.L. Jiang ◽  
Y. Chen ◽  
H.M. Chen
Keyword(s):  
Exchange Coupling ◽  
Permanent Magnets ◽  
Coupling Effect ◽  
Maximum Energy ◽  
Soft Magnetic ◽  
Magnetic Phases ◽  
Maximum Energy Product ◽  
Energy Product ◽  
High Maximum ◽  
Intrinsic Coercivity

Nd2Fe14B/-Fe nanocomposite permanent magnet contains the hard and soft magnetic phases, Nd2Fe14B and -Fe respectively. An exchange coupling effect exists between the two magnetic phases. The effect of alloying element Nb on its nanostructure and properties have been studied. Adding Nb to the alloy is effective to refine grains, a relatively small grain size causes a high intrinsic coercivity, remanence and therefore a high maximum energy product, (BH)max. MFM (Magnetic Force Microscope) was used to observe the magnetic micro-domain structure in the nanophase alloys. The length of the magnetic contrast shows a significant dependence on the microstructure and phase constitution, and the longer length is correspond with the larger exchange coupling effect between the soft and hard magnetic phases.

Magnetic Silicone Rubbers

1983 ◽  
Vol 56 (2) ◽  
pp. 322-326 ◽  
Author(s):  
Petra Štefcová ◽  
Miroslav Schatz
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Silicone Rubber ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Silicone Rubbers

Abstract The method of preparation of elastic permanent magnets of silicone rubber is described, and the values of the basic magnetic properties of these rubbers, i.e., the coercive force, the remanent induction, and the maximum energy product, are given.

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