Nanocrystalline and nanocomposite permanent magnets by melt spinning technique

2018 ◽  
Vol 27 (11) ◽  
pp. 117502 ◽  
Author(s):  
Chuanbing Rong ◽  
Baogen Shen
Keyword(s):  
Melt Spinning ◽  
Permanent Magnets ◽  
Melt Spinning Technique

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.

Rapidly Solidified Melt-spun Bi-Sn Ribbons: Surface Composition Issues

2016 ◽  
pp. 3287-3297
Author(s):  
Tarek El Ashram ◽  
Ana P. Carapeto ◽  
Ana M. Botelho do Rego
Keyword(s):  
Chemical Composition ◽  
Optical Microscopy ◽  
Melt Spinning ◽  
Surface Composition ◽  
Electrochemical Process ◽  
Melt Spun ◽  
Bismuth Alloy ◽  
The One ◽  
Rapidly Solidified ◽  
Melt Spinning Technique

Tin-bismuth alloy ribbons were produced using melt-spinning technique. The two main surfaces (in contact with the rotating wheel and exposed to the air) were characterized with Optical Microscopy and AFM, revealing that the surface exposed to the air is duller (due to a long-range heterogeneity) than the opposite surface. Also the XPS chemical composition revealed many differences between them both on the corrosion extension and on the total relative amounts of tin and bismuth. For instance, for the specific case of an alloy with a composition Bi-4 wt % Sn, the XPS atomic ratios Sn/Bi are 1.1 and 3.7 for the surface in contact with the rotating wheel and for the one exposed to air, respectively, showing, additionally, that a large segregation of tin at the surface exists (nominal ratio should be 0.073). This segregation was interpreted as the result of the electrochemical process yielding the corrosion products.

Microstructural Studies of NiCoMnIn Magnetic Shape Memory Ribbons

2013 ◽  
Vol 738-739 ◽  
pp. 436-440 ◽  
Author(s):  
Krystian Prusik ◽  
Katarzyna Bałdys ◽  
Danuta Stróż ◽  
Tomasz Goryczka ◽  
Józef Lelątko
Keyword(s):  
Melt Spinning ◽  
Room Temperature ◽  
Parent Phase ◽  
Magnetic Shape Memory ◽  
Melt Spun ◽  
Columnar Grains ◽  
Ebsd Technique ◽  
Microstructural Studies ◽  
Melt Spinning Technique ◽  
Scanning Electron

In present paper two ribbons of the Ni44Co6Mn36In14 (at.%) were prepared under different melt-spinning technique conditions. Microstructure of the ribbons was studied by scanning electron microscopy (SEM). Depending on the liquid ejection overpressure two types of ribbons microstructures were observed. Ribbon T1 for which ejection overpressure was 1.5 bar showed typical melt-spun ribbon microstructure consisting of a top layer of small equi-axial grains and columnar grains below. For T2 ribbon (ejection overpressure 0.2 bar) only a small fraction of the columnar grains were observed. Structure analysis of the ribbons performed by XRD showed that at room temperature both ribbons have B2 parent phase superstructure. No gamma phase precipitates were observed. In order to determine the orientation of the grains the EBSD technique was applied.

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.

Synthesis and Characterization of Mnbi Magnetic Alloy via Two Different Processing Routes

2021 ◽  
Vol 875 ◽  
pp. 76-80
Author(s):  
Hifsa Mazhar ◽  
Wilayat Hussain
Keyword(s):  
Heat Treatment ◽  
Melt Spinning ◽  
Treatment Time ◽  
Magnetic Energy ◽  
Microstructural Characterization ◽  
Temperature Phase ◽  
Magnetic Alloy ◽  
Positive Temperature ◽  
Melt Spinning Technique

Manganese bismuth alloy has gained importance due to its rare earth free elements, positive temperature coefficient and unique magnetic properties. Low temperature phase (LTP) MnBi was successfully prepared by arc melting with subsequent heat treatments and melt spinning technique followed by heat treatment for different durations. LTP MnBi formation was confirmed using XRD analysis and microstructural characterization of the samples was done using field emission scanning electron microscope. MnBi with greater LTP amount was formed by melt spinning route when compared with its counter arc melted one. Magnetic energy density of LTP MnBi formed by melt spinning technique with different heat treatment time was studied.

New, Experimental Powder Diffraction Data for Metastable Fe3B Phase Prepared According to ICDD Standards

2010 ◽  
Vol 163 ◽  
pp. 173-176
Author(s):  
Lucjan Pająk ◽  
E. Olszewska ◽  
Stanislaw Pikus ◽  
Grzegorz Dercz ◽  
Józef Rasek
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Melt Spinning ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Graphite Monochromator ◽  
Best Fitting ◽  
Melt Spinning Technique

In the present work X-ray studies were performed on annealed Fe78Nb2B20 amorphous alloy prepared by melt-spinning technique. All the samples were annealed in vacuum for 1 hour at temperatures up to 800°C. For the studied alloy -Fe and Fe2B are the stable, crystalline phases. The -Fe crystallized as the first crystalline phase in the sample annealed at 350°C. On the other hand, metastable Fe3B phase appeared to be stable during annealing in 425-800°C temperature range. The best fitting of the experimental X-ray data to as jet available ICDD files was obtained for Ni3P type structure (39-1315 – S.G.: I (82)). New, experimental powder diffraction data for metastable Fe3B phase prepared according to ICDD standards were elaborated for the sample annealed at 600°C. For this sample the best agreement between the calculated values of lattice constants and positions of experimental diffraction lines was obtained. The X-ray data were collected using X-Pert Philips diffractometer equipped with curved graphite monochromator on diffracted beam. The Treor program was applied for the analysis of X-ray diffraction data.

Giant Magnetoimpedance in as Quenched Fe Based Nanocrystalline Ribbons

2005 ◽  
Vol 475-479 ◽  
pp. 2219-2222 ◽  
Author(s):  
Ji Fan Hu ◽  
Hong Wei Qin ◽  
Minhua Jiang ◽  
Bo Li ◽  
Dongliang Zhao ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Materials ◽  
Melt Spinning ◽  
Experimental Results ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Giant Magnetoimpedance ◽  
Giant Magnetoimpedance Effect ◽  
Additional Annealing ◽  
Melt Spinning Technique

FeCuNbSiB and FeZrBCu nanocrystalline ribbons can be obtained directly through the melt- spinning technique without additional annealing processes. The giant magnetoimpedance can be observed in FeCuNbSiB and FeZrBCu as quenched ribbons. The addition of Cu improves the nano-crystallization of a-Fe(Si) or a-Fe phase and reduces the grain size in FeCuNbSiB and FeZrBCu as quenched ribbons, which enhances the magnetoimpedance via increasing the variation of permeability under fields. The present experimental results reveal a novel route to fabricate the Fe based nanocrystalline soft magnetic materials with giant magnetoimpedance effect.

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