scholarly journals Amorphization, Crystallization, and Magnetic Properties of Melt-Spun SmCo7−x(Cr3C2)x Alloys

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Liya Li ◽  
Wei Xie
Keyword(s):  
Magnetic Properties ◽  
Exchange Coupling ◽  
Melt Spinning ◽  
Amorphous State ◽  
Wheel Surface ◽  
Amorphous Phases ◽  
Annealed Ribbon ◽  
Melt Spun ◽  
Interaction Domains ◽  
Strong Exchange

Effects of Cr3C2 content and wheel surface speed on the amorphous formation ability and magnetic properties have been investigated for melt-spun SmCo7−x(Cr3C2)x (x=0.10-0.25) alloys. Ribbon melt-spun at lower wheel speed (30 m/s) has composite structure composed of mostly SmCo7, a small amount of Sm2Co17, and residual amorphous phases. The grain size of SmCo7 phase decreases with the increase of Cr3C2 content x. When melt spinning at 40 m/s, SmCo7−x(Cr3C2)x alloys can be obtained in the amorphous state for 0.15≤x≤0.25 with intrinsic coercive Hci of the order of 40–70 Oe. DSC analysis reveals that SmCo7 phase first precipitates from the amorphous matrix at 650∘C, followed by the crystallization of Sm2Co17 phase at 770∘C. Optimal coercivity Hci of 7.98 kOe and remanent magnetization Mr of 55.05 emu/g have been realized in SmCo6.8(Cr3C2)0.20 magnet subjected to melt spinning at 40 m/s and annealing at 650∘C for 5 min. The domain structure of the annealed ribbon is composed of interaction domains typically 100–400 nm in size, which indicates the presence of a strong exchange coupling between the grains.

Magnetic Structure and Magnetization Reversal in Nanocomposite Pr2Fe14B/α-Fe Ribbons

2005 ◽  
Vol 475-479 ◽  
pp. 2127-2130
Author(s):  
Xiaoqian Bao ◽  
Mao Cai Zhang ◽  
Yi Qiao ◽  
Shouzeng Zhou
Keyword(s):  
Magnetization Reversal ◽  
Exchange Coupling ◽  
Melt Spinning ◽  
Magnetic Force ◽  
Permanent Magnets ◽  
Soft Magnetic ◽  
Force Microscopy ◽  
Interaction Domains ◽  
Strong Exchange ◽  
Pinning Field

Nanocomposite Pr7.5Dy1Fe71Co15Nb1B4.5 ribbons were prepared by melt-spinning and subsequent annealing. Interaction domains were imaged using magnetic force microscopy (MFM) because of strong exchange coupling between hard and soft magnetic grains. Coercivity was determined by exchange coupling pinning field. But the magnetization reversal of nanocomposite magnets were different from that of traditional single phase permanent magnets.

Effect of Wheel Speeds on the Microstructure and Magnetic Properties of Melt-Spun (Nd0.75,Dy0.25)10.5 Zr2Fe82B5.5 Ribbons

2012 ◽  
Vol 569 ◽  
pp. 23-26 ◽  
Author(s):  
Jie Qiu ◽  
Shan Dong Li ◽  
Mei Mei Liu ◽  
Jian Peng Wu ◽  
Yi Hu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Exchange Coupling ◽  
Wheel Speed ◽  
Coupling Interaction ◽  
Nanocomposite Structure ◽  
Melt Spun ◽  
Exchange Coupling Interaction ◽  
Strong Exchange ◽  
Microstructure And Magnetic Properties

Nanocomposite (Nd,Dy)2Fe14B/α-Fe magnets were prepared by directly solidification (DS). The effect of wheel speed on the magnetic properties, microstructure and exchange coupling interaction has been studied. It was found that a uniform R2Fe14B/α-Fe nanocomposite structure with fine α-Fe grains can be developed at an optimum wheel speed of about 18 m/s. Without any heat treatment, the optimal ribbons (v = 18 m/s) show a strong exchange coupling interaction and good magnetic properties, e.g. iHc=1027 kA/m, mr =0.71, (BH)max=174 kJ/m3.

Influence of Co-Doping on Magnetic Properties and Magnetocaloric Effect of Fe–Co–Zr–Cu–B Melt-Spun Ribbons

2021 ◽  
Vol 21 (4) ◽  
pp. 2552-2557
Author(s):  
Nguyen Hai Yen ◽  
Nguyen Hoang Ha ◽  
Pham Thi Thanh ◽  
Nguyen Huy Ngoc ◽  
Tran Dang Thanh ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetocaloric Effect ◽  
Melt Spinning ◽  
Room Temperature ◽  
Tangential Velocity ◽  
Magnetic Behavior ◽  
Entropy Change ◽  
Co Doping ◽  
Melt Spun ◽  
Melt Spun Ribbons

In this work, we investigated magnetic properties and magnetocaloric effect in Fe90−xCoxZr7Cu1B2 (x = 0, 1, 2, 3 and 4) melt-spun ribbons. The ribbons were prepared by using a melt-spinning method with a tangential velocity of a copper wheel of 40 m·s-1. The obtained ribbons are almost amorphous. The alloys exhibit typical soft magnetic behavior with low coercivity at room temperature. A minor replacement of Fe by Co gives an increment in Curie temperature (TC) of the alloys to higher temperatures. The TC of the alloys increases from 242 to 342 K with an increase of x from 0 to 4. Maximum magnetic entropy change, ΔSm max, of the alloys, was found to be larger than 0.7 J·kg-1·K-1 in a magnetic field change ΔH of 12 kOe for all the concentrations of Co. High refrigerant capacitys (RC >100 J ·kg-1 with ΔH = 12 kOe) at room temperature region have been obtained for the alloys. The large magnetocaloric effect near room temperature suggests that the alloys can be considered as magnetic refrigerants in the range of 250–350 K.

PHASE EVOLUTION AND MAGNETIC PROPERTIES OF TbCu7-TYPE (Sm, Pr)Co7-xHfxMy (x = 0-0.5; y = 0-0.14) RIBBONS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1663-1669 ◽  
Author(s):  
H. W. Chang ◽  
S. T. Huang ◽  
I. W. Chen ◽  
C. W. Chang ◽  
W. C. Chang
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Exchange Coupling ◽  
Coupling Effect ◽  
Anisotropy Field ◽  
Phase Evolution ◽  
Phase Constitution ◽  
Melt Spun

The effects of Hf substitution and C content on the magnetic properties, phase evolution, and microstructure of melt spun ( Sm , Pr ) Co 7- x Hf x C y ( x = 0-0.5; y = 0-0.14) ribbons have been studied. A proper Hf substitution is helpful not only in stabilizing 1:7 phase but also in enhancing its magnetic anisotropy field. As a result, magnetic properties of B r = 6.4 kG , i H c = 7.3 kOe and ( BH ) max = 8.7 MGOe for SmCo 6.9 Hf 0.1 ribbons are obtained. Besides, a small amount of C addition in the ribbons could slightly modify phase constitution and effectively refine their microstructure to strengthen the exchange coupling effect between magnetic grains. Furthermore, a slight Pr substitution for Sm may further increase the magnetization and the magnetic properties of the ribbons. The optimal magnetic properties of B r = 7.1 kG , i H c = 8.5 kOe and ( BH ) max = 11.2 MGOe could be achieved for the directly quenched Sm 0.8 Pr 0.2 Co 6.9 Hf 0.1 C 0.12 ribbons.

EVOLUTION OF NANOGRAINS AND SOFT MAGNETIC PROPERTIES OF Fe74Cu0.8Nb2.7Si15.5B7 BY ISOTHERMAL ANNEALING

2011 ◽  
Vol 25 (14) ◽  
pp. 1241-1251 ◽  
Author(s):  
SHEIKH MANJURA HOQUE ◽  
UMASREE DHAR ◽  
M. A. HAKIM ◽  
D. K. SAHA ◽  
HARI NARAYAN DAS
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Isothermal Annealing ◽  
Amorphous State ◽  
Initial Permeability ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Type Composition ◽  
Long Time ◽  
Short Time

Fe -based alloy of the composition, Fe 74 Cu 0.8 Nb 2.7 Si 15.5 B 7 has been studied thoroughly in order to research the evolution of nanograins and soft magnetic properties. The composition has been significantly deviated from FINEMET type composition given by Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9. It is hard to optimize composition to obtain equally good soft magnetic properties as FINEMET significantly deviating from conventional type alloy. Fe -based alloy of the composition, Fe 74 Cu 0.8 Nb 2.7 Si 15.5 B 7 has been prepared by single roller melt spinning machine. X-ray diffraction studies confirmed that the ribbon is in the amorphous state. Evolution of α- Fe ( Si ) nanograins from amorphous matrix were carried out by isothermal annealing in the temperature range from 550°C to 650°C for 1, 3, 5, 10, 20, 30, 40, 50 and 60 minutes. Frequency spectrum of real and imaginary part of complex initial permeability has been measured for the samples at different annealing conditions. Short time annealing has been proved to be more efficient than long time annealing for the samples of this composition for most of the annealing temperatures.

Preparation and Magnetic Properties of the Exchange Coupling NdFeB Nanocomposited Permanent Magnets

2007 ◽  
Author(s):  
Zongjun Tian ◽  
Shangdong Li ◽  
Youwei Du ◽  
Yinhui Huang
Keyword(s):  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Grain Boundaries ◽  
Exchange Coupling ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Energy Product ◽  
Remanence Ratio ◽  
Optimum Energy ◽  
Hard Magnetic Properties

The effect of indium additions on the microstructures and magnetic properties of Nd9Fe85−xB6Inx (x = 0–2) nanocomposites prepared by melt spinning was investigated. It was found that a certain amount of indium added to Nd9Fe85B6 magnets enhances the hard magnetic properties. The coercivity and remanence ratio of the magnet with 0.5 at.% indium increases from 405kA/m (no indium) to 465kA/m and from 0.7 to 0.86 respectively. Squareness of its hysteresis loop is also improved greatly. The optimum energy product (BH)max increases remarkably from 95kJ/m3 to 145kJ/m3. The origin for those enhancements is mainly attributed to the magnetically softened grain boundaries and enhanced crystallographical coherency by indium addition. The magnetic annealing is found to be helpful to enhance the coherency and coupling between hard and soft phases.

HIGH MAGNETIC PROPERTIES OF TbCu7-TYPE MELT SPUN (Sm, Pr)Co7-xHfxCy RIBBONS

2008 ◽  
Vol 01 (03) ◽  
pp. 183-187 ◽  
Author(s):  
H. W. CHANG ◽  
S. T. HUANG ◽  
I. W. CHEN ◽  
C. W. CHANG ◽  
W. C. CHANG
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Exchange Coupling ◽  
Coupling Effect ◽  
Anisotropy Field ◽  
Phase Evolution ◽  
Phase Constitution ◽  
Melt Spun

The effects of Hf substitution and C content on the magnetic properties, phase evolution and microstructure of melt spun ( Sm , Pr ) Co 7-x Hf x C y (x = 0–0.5; y = 0–0.14) ribbons have been studied. A proper Hf substitution is helpful not only in stabilizing 1:7 phase but also in enhancing its magnetic anisotropy field, as a result, magnetic properties of B r = 6.4 kG , i H c = 7.3 kOe and (BH) max = 8.7 MGOe for SmCo 6.9 Hf 0.1 ribbons are obtained. Besides, a small amount of C addition in the ribbons could slightly modify phase constitution and effectively refine their microstructure to strengthen the exchange coupling effect between magnetic grains. It leads to the improvement of the magnetic properties for SmCo 6.8 Hf 0.2 C 0.12 nanocomposites. Finally, a slight Pr substitution for Sm may further increase the magnetization and the magnetic properties, the optimal magnetic properties of B r = 7.1 kG , i H c = 8.5 kOe and (BH) max = 11.2 MGOe could be achieved for the directly quenched Sm 0.8 Pr 0.2 Co 6.9 Hf 0.1 C 0.12 ribbons.

The Microstructure of Melt-Spun Iron Neodymium Permanent Magnet Materials

1985 ◽  
Vol 43 ◽  
pp. 210-211
Author(s):  
R. C. Dickenson
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Melt Spinning ◽  
Ion Milling ◽  
X Ray ◽  
Fine Grained ◽  
Cold Stage ◽  
Melt Spun ◽  
Fine Grained Structure ◽  
Permanent Magnet Materials

Rapidly-quenched iron rare-earth boron alloys, with appropriate heat treatment, exhibit commercially promising permanent magnetic properties. This paper will report the results of an AEM characterization undertaken to explain the origin of the magnetic properties of an iron-neodymium-boron alloy in terms of its microstructure. Ribbons of Fe76 Nd16 B8 were prepared by melt-spinning, and were subsequently annealed at 700°C for 6 minutes to promote growth of a fine-grained structure. Samples were prepared for AEM by ion-milling the ribbons on a cold stage and examined using a Philips 400T TEM/STEM equipped with an energy dispersive x-ray unit.Three different microstructures are commonly observed in these alloys, and several others have been found in isolated cases.

Microstructure and Magnetic Properties of (Nd1-2xPrxYx)2.28Fe13.58B1.14 Melt-Spun Alloys

2017 ◽  
Vol 898 ◽  
pp. 1242-1246
Author(s):  
M.H. Rong ◽  
J. Ma ◽  
Jiang Wang ◽  
H.Y. Zhou ◽  
G.H. Rao
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Physical Property Measurement System ◽  
Physical Property ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Melt Spun

As a rapid solidification technology, strip casting (SC) technology is one of importance method in the production of Nd2Fe14B-based rare-earth permanent magnets. (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) alloys prepared by arc melting method under an argon atmosphere were annealed at 1173 K for 360 hrs and then were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC). Magnetic properties of the ribbons prepared by melt-spinning method with high cooling rate were measured by Physical Property Measurement System (PPMS). The XRD and SEM results showed that the annealed (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.10, 0.15, 0.20) alloys had a single phase with tetragonal Nd2Fe14B-tpyed structure, while the annealed (Nd0.90Pr0.05Y0.05)2.28Fe13.58B1.14 alloy contained Nd2Fe14B phase and α-Fe secondary phase. On the other hand, the coercivities (Hcj) of (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) melt-spun alloys were about 13.42 kOe, 13.49 kOe, 7.97 kOe and 8.36 kOe, respectively, while the remanences (Br) of the alloys were 7.52 kGs, 7.48 kGs, 9.14 kGs and 7.48 kGs, respectively. In addition, The Curie temperature (Tc) of the annealed (Nd1-2xPrxYx)2.28Fe13.58B1.14 (x=0.05, 0.10, 0.15, 0.20) alloys were determined to be 573 K, 574 K, 579 K and 580 K, respectively.

Crystallization and Magnetic Properties of Melt-Spun SmCo7-x(Cr3C2)x Alloys

2013 ◽  
Vol 321-324 ◽  
pp. 125-128
Author(s):  
Li Ya Li ◽  
Jian Hong Yi ◽  
Yuan Dong Peng
Keyword(s):  
Magnetic Properties ◽  
Amorphous State ◽  
Domain Size ◽  
Amorphous Structure ◽  
Soft Magnetic ◽  
Interaction Domain ◽  
Melt Spun ◽  
Average Size ◽  
Individual Grains ◽  
20 Nm

The amorphous formation ability, crystallization behavior and magnetic properties of SmCo7 magnets melt-spun at 30 and 40 m/s have been studied. The ribbons melt-spun at 40 m/s exhibit amorphous structure in the range of 0.15x0.25 for SmCo7-x(Cr3C2)x alloys. In the amorphous state, these alloys are soft magnetic with intrinsic coercive field iHc of the order of 40-70 Oe. After annealing at 750 °C for 5 min, the alloy shows enhenced magnetic properties with iHc of 7.98 kOe, Mr of 55.05 emu/g, and Mr of 70.99 emu/g. The MFM image reveals a uniform distribution of individual grains with average size about 20 nm and a domain size about 100250 nm in width. This interaction domain results in the enhancement of the magnetic properties.

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