Magnetic Domain Structure of Nanocrystalline Zr18-xHfxCo82 Ribbons: Effect of Hf

2013 ◽  
Vol 1557 ◽  
Author(s):  
Lanping Yue ◽  
I. A. Al-Omari ◽  
Wenyong Zhang ◽  
Ralph Skomski ◽  
D. J. Sellmyer
Keyword(s):  
Magnetic Properties ◽  
Domain Structure ◽  
Structure Refinement ◽  
Magnetic Domain ◽  
Maximum Energy ◽  
Magnetic Domain Structure ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Domain Structures ◽  
Rapidly Solidified

ABSTRACTThe effect of Hf on the permanent magnetism of nanocrystalline Zr18-xHfxCo82 ribbons (x = 0, 2, 4, and 6) was investigated by magnetic properties measurement and magnetic force microscopy (MFM). Emphasis is on the local magnetic domain structures in polycrystalline rapidly solidified Zr18-xHfxCo82 ribbons for four different samples with small fractions of Hf dopants (x ≤ 6). The investigation of the magnetic properties of the Zr18-xHfxCo82 ribbons revealed that all the samples under investigation are ferromagnetic at room temperature, and the corresponding MFM images show bright and dark contrast patterns with up-down magnetic domain structures. It is found that the saturation magnetization and the coercivity depend on Hf doping concentration x in the samples. For a sample with Hf concentration x = 4, the maximum energy product (BH)max value is 3.7 MGOe. The short magnetic correlation length of 131 nm and smallest root-mean-square phase shift value of 0.680 were observed for x = 4, which suggests the refinement of the magnetic domain structure due to weak intergranular exchange coupling in this sample. The above results indicate that suitable Hf addition is helpful for the magnetic domain structure refinement, the coecivity enhancement, and the energy-product improvement of this class of rare-earth-free nanocrystalline permanent-magnet materials.

Effect of Boron Addition on Magnetic-Domain Structure of Rapidly Quenched Zr2Co11−Based Nanomaterials

MRS Advances ◽  
2016 ◽  
Vol 1 (34) ◽  
pp. 2379-2385 ◽  
Author(s):  
Lanping Yue ◽  
Yunlong Jin ◽  
David J. Sellmyer
Keyword(s):  
Magnetic Properties ◽  
Domain Structure ◽  
Structure Refinement ◽  
Magnetic Domain ◽  
Domain Size ◽  
Maximum Energy ◽  
Magnetic Domain Structure ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Domain Structures

ABSTRACTThe boron-content dependence of magnetic domain structures and magnetic properties of nanocrystalline Zr16Co82.5−xMo1.5Bx (x = 0, 1, 2, 3, 4) melt-spun ribbons have been investigated. Compared to x = 0, the smaller average domain size with a relatively short magnetic correlation length of 120 nm and largest root-mean-square phase shift value of 0.94° are observed for x = 1. The best magnetic properties of coercivity Hc = 5.4 kOe, maximum energy product (BH)max = 4.1 MGOe, and saturation polarization Js = 7.8 kG, were obtained for the ribbon with x = 1. The optimal B addition enhances the content of hard magnetic phase, promotes magnetic domain structure refinement, and increases the surface roughness, results in the enhancement of magnetic anisotropy, and thus leads to a significant increase in coercivity and energy product in this sample.

scholarly journals Magnetic Force Microscopy Study ofZr2Co11-Based Nanocrystalline Materials: Effect of Mo Addition

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Lanping Yue ◽  
Yunlong Jin ◽  
Wenyong Zhang ◽  
David J. Sellmyer
Keyword(s):  
Permanent Magnets ◽  
Structure Refinement ◽  
Magnetic Domain ◽  
Domain Size ◽  
Microscopy Study ◽  
Maximum Energy ◽  
Local Domain ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Domain Structures

The addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr2Co11-based nanocrystalline permanent magnets. The effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr16Co84-xMox(x=0, 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. The coercivity of the samples increases with the increase in Mo content (x≤1.5). The maximum energy product(BH)maxincreases with increasingxfrom 0.5 MGOe forx=0to a maximum value of 4.2 MGOe forx=1.5. The smallest domain size with a relatively short magnetic correlation length of 128 nm and largest root-mean-square phase shiftΦrmsvalue of 0.66° are observed for thex=1.5. The optimal Mo addition promotes magnetic domain structure refinement and thus leads to a significant increase in coercivity and energy product in this sample.

Improved thermal stability of hard magnetic properties in rapidly solidified RE–TM–B alloys

2008 ◽  
Vol 23 (10) ◽  
pp. 2733-2742 ◽  
Author(s):  
Z.W. Liu ◽  
R.V. Ramanujan ◽  
H.A. Davies
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Magnetic Properties ◽  
Elevated Temperature ◽  
Melt Spinning ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Rapidly Solidified ◽  
Hard Magnetic Properties

Rapidly solidified nanocrystalline RE–TM–B (RE = Nd, Pr, Dy, TM = Fe, Co) alloys with enhanced hard magnetic properties were synthesized by melt spinning. The composition- and microstructure-dependent elevated temperature magnetic properties were investigated. The temperature coefficients of remanence (α) and coercivity (β) were determined. The effects of Pr substituting Nd, Co substituting Fe, Dy substituting RE, and grain size on the Curie temperature and thermal stability were studied. Co or Dy substitutions were found to have a significant beneficial effect on the thermal stability. Reducing grain size could also improve elevated temperature behavior. Maximum energy product (BH)max > 100 kJ/m3 could be obtained in compositionally optimized nanophase alloys at temperature of 473 K. Extremely low coefficients of α and β were realized in exchange coupled nanocomposite alloys. Bonded nanocomposite magnets with α = −0.052%/K and β = −0.0365%/K for 300–400 K were also successfully fabricated.

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.

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.

New YDy-Based R2(Fe,Co)14B Melt-Spun Magnets (R=Y+Dy+Nd)

2005 ◽  
Vol 475-479 ◽  
pp. 2155-2160 ◽  
Author(s):  
W. Tang ◽  
K.W. Dennis ◽  
Matthew J. Kramer ◽  
I.E. Anderson ◽  
R.W. McCallum
Keyword(s):  
Magnetic Properties ◽  
High Temperature ◽  
Temperature Coefficient ◽  
Temperature Stability ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Optimal Sample ◽  
Melt Spun ◽  
Nd Substitution

The effects of the ratio of Y to Dy as well as the effect of Nd and Co substitutions on magnetic properties in [Ndx(YDy)0.5(1-x)]2.2Fe14-yCoyB ribbons melt-spun at 22 m/s have been systematically studied. (Y1-zDyz)2.2Fe14B ribbons with a ratio z of 0.25 or 0.5 simultaneously obtains a smaller temperature coefficient of remanence (α ) and coervicity (β ) which are much smaller than those of Nd-based Nd2Fe14B ribbons. In [Ndx(YDy)0.5(1-x)]2.2Fe14-yCoyB ribbons, Nd substitution (x=0 to 0.8) can improve the maximum energy product (BH)max of annealed ribbons but degrades the temperature stability of the magnetic properties. The ribbons with x=0.4 and y=0 yield a (BH)max of 8.7 MGOe. For these ribbons, the α and β are -0.07 and -0.31 %/°C in the temperature range of 27 to 127°C, respectively. Increasing Co (x) from 0 to 3, slightly decreases coercivity Hcj from 21.5 to 16.3 kOe, but keeps the (BH)max in the range of 8.6 to 10.2 MGOe. The optimal sample with x=0.5 and y=1.5 obtains a (BH)max of 10.2 and 5.0 MGOe at 27 and 250°C, respectively. Its α and β are -0.11 and -0.30 %/°C, respectively. These results show that studied ribbons are very promising to develop into high temperature isotropic bonded magnets capable of operating at or above 180°C.

scholarly journals Nanocrystalline Nd-Fe-B Alloys for Polymer-Bonded Magnets Production

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Aleksandar Grujić ◽  
Vladan Ćosović ◽  
Aleksandar Ćosović ◽  
Jasna Stajić-Trošić
Keyword(s):  
Magnetic Properties ◽  
Exchange Coupling ◽  
Magnetic Phase ◽  
Coupling Effect ◽  
Maximum Energy ◽  
Soft Magnetic ◽  
Nanocomposite Structure ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Composite Production

This study presents how different nanostructures of starting Nd-Fe-B particles have influence on magnetic properties of polymer-bonded Nd-Fe-B materials. Two types of nanocrystalline Nd-Fe-B alloys were used for polymer composite production by compression molding technique. The particles with low neodymium content (Nd-low) have nanocomposite structure with small exchange coupling effect between hard and soft magnetic phase. In other hand, practically monophase hard magnetic structure of Nd-Fe-B particles with stoichiometric neodymium content (Nd-stoich) shows improved magnetic properties. With increasing concentration of polymer matrix, the coercivity (Hcb), remanence (Br), and maximum energy product ((BH)max) decrease more prominenty for composites with stoichiometric Nd-Fe-B content.

ALNICO-V-7

Alloy Digest ◽  
1966 ◽  
Vol 15 (10) ◽  
Keyword(s):  
Magnetic Properties ◽  
Cast Alloy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Iron Aluminum ◽  
Nickel Cobalt ◽  
Magnet Alloy ◽  
Engineering Company ◽  
Permanent Magnet Alloy

Abstract ALNICO V-7 is a heat treatable cast alloy of iron, aluminum, nickel, cobalt and copper. It is a permanent magnet alloy having directional magnetic properties and a maximum energy product of 7,500,000 gauss-oersteds. (Also known as ALNICO 5-7) This datasheet provides information on composition, physical properties, hardness, and tensile properties. Filing Code: Fe-29. Producer or source: Arnold Engineering Company.

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