Influence of Alloying Elements Zr, Nb and Mo on the Microstructure and Magnetic Properties of Sintered Pr-Fe-Co-B Based Permanent Magnets

2018 ◽  
Vol 930 ◽  
pp. 440-444
Author(s):  
Melissa Rohrig Martins da Silva ◽  
R.G.T. Fim ◽  
S.C. Silva ◽  
Julio Cesar Serafim Casini ◽  
P.A.P. Wendhausen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
Alloying Elements ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Cast Alloys ◽  
Hydrogen Decrepitation ◽  
Microstructure And Magnetic Properties

The addition of alloying elements on rare-earth permanent magnets is one of the methods used to improve the magnetic properties. This present work evaluates the influence of alloying elements such as Zr, Nb and Mo on the microstructure and magnetic properties of sintered Pr-FeCo-B based permanent magnets. The permanent magnets were produced by the conventional powder metallurgy route using powder obtained by hydrogen-decrepitation (HD) method from as cast alloys. In order to produce the magnet Pr16Fe66,9Co10,7B5,7Cu0,7 without alloying elements the mixture of alloys method was employed, mixing two compositions: Pr20Fe73B5Cu2 (33% w.t) and Pr14Fe64Co16B6 (67% w.t). With the purpose of evaluating the influence of the alloying elements, the Pr14Fe64Co16B6X0,1 (where X= Zr, Nb or Mo) (67% w.t) alloy was employed. The characterization of the alloys and the magnets was carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS) and the magnetic properties were measured using a permeameter. The magnet without any additions presented the highest intrinsic coercivity (μ0iHc = 748 KA.m-1) while the magnet with Nb addition presented higher remanence (Br = 1,04 T). The magnet with Zr addition presented the highest maximum energy product (BHmáx = 144 KJ.m-3), and the magnet with Mo addition showed the highest squareness factor (SF = 0,73).

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.

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.

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.

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.

Effects of Co, Zr Additions on the Magnetic Properties of Nanocomposite Nd2Fe14B/α-Fe Magnets

2017 ◽  
Vol 898 ◽  
pp. 2128-2133 ◽  
Author(s):  
Bing Bing Li ◽  
Yi Long Ma ◽  
Chun Hong Li ◽  
Xue Guo Yin ◽  
Qiang Zheng ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Zn Addition ◽  
Coarse Grains ◽  
Axis Alignment ◽  
Co Addition ◽  
Uniform Composition ◽  
Microstructure And Magnetic Properties

The effects of the additions of Co, Zr on microstructure and magnetic properties were studied for hot-deformed (HD) nanocomposite Nd11.5Fe81.5-xNb1CoxB6 (x=0, 2, 4, 8) and Nd11.5Fe82.5-xZrxB6 (x=0, 1) magnets, respectively. The remanence of hot-pressed (HP) magnets increased with increasing Co content firstly, but decreased when Co content was more than 2 at. % for HD magnets. Also the intrinsic coercivity (Hci) and maximum energy product ((BH)m) of HD alloys increased firstly, and then decreased with further increasing Co content. The maximum (BH)m of 24 MGOe was obtained at 2 at.% Co addition. Zr addition can improve significantly the c-axis alignment and magnetic properties of HD nanocomposite magnets, and HD Nd11.5Fe81.5Zr1B6 magnet with 1.5 wt.% Zn addition showed enhanced properties with Hci of 7100 Oe and remanent magnetization (Mr) of 1.06 T. The alloys have the structure of plate-like grains, but there are still many coarse grains, which may result from the un-uniform composition in the alloy.

Microstructural and Magnetic Properties of a Fe-Co-Ni-Al-Ti-Cu Alloy

2010 ◽  
Vol 442 ◽  
pp. 236-241 ◽  
Author(s):  
S. Akbar ◽  
Z. Ahmad ◽  
M. Farooque
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
X Ray Diffraction ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Cu Alloy ◽  
Treatment Conditions ◽  
Residual Magnetic Induction ◽  
Microstructural Studies

The present work describes the development of Fe-Co-Ni-Al-Ti-Cu permanent magnets. Magnetic and microstructural studies were carried out using microscopy, magnetometery and X-ray diffraction techniques. The results indicate that both microstructural and magnetic properties are sensitive to the heat treatment conditions. Magnetic properties in the studied alloys could be improved by controlling the annealed state microstructure and by efficiently aligning and elongating the nano-structured ferromagnetic α1 particles in <001> crystallographic directions. The best magnetic properties in the alloy Fe-34.7Co-15.3Ni-8.3Al-5.4Ti-3.9Cu is obtained as coercive force (Hc) of 1528Oe, residual magnetic induction (Br) of 7105G, saturation magnetization (Bs) of 19060G and maximum energy product ((BH)max) of 3.3MGOe.

Study on Microstructure and Magnetic Properties of Nitrogen-Annealed Nd-Fe-B Nanocomposite Magnets

2012 ◽  
Vol 476-478 ◽  
pp. 1130-1133
Author(s):  
Chen Wang ◽  
Jun Jun Chen ◽  
Pin Qiang Dai ◽  
Qiang Li
Keyword(s):  
Magnetic Properties ◽  
Nitrogen Content ◽  
Maximum Energy ◽  
Coarse Grained ◽  
Annealing Atmosphere ◽  
Fine Grained ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Nitrogen Annealing ◽  
Microstructure And Magnetic Properties

The effects of nitrogen annealing on the microstructure and magnetic properties of melt-spun Nd-Fe-Co-Zr-B alloy have been studied. It is shown that the ribbons annealed in purified argon atmosphere are composed of Nd2Fe14B and α-Fe phases, the microstructure of ribbons is homogeneous and fine-grained. The nitrogen-annealed ribbons are composed of Nd2Fe14B, NdBN2and α-Fe phases, the microstructure of ribbons is relatively heterogeneous and coarse-grained. The increase of nitrogen content in the annealing atmosphere can increase the volume fractions of NdBN2and α-Fe phases in the ribbons. The remanence, intrinsic coercivity and the maximum energy product of ribbons are decreased with increasing the nitrogen content in the annealing atmosphere.

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.

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.

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