Cryogenic ball milling synthesis of L10-Mn55Ga45/FeCo composites with effective exchange coupling and enhanced maximum energy products

2018 ◽  
Vol 231 ◽  
pp. 167-170
Author(s):  
Ning Pang ◽  
Feng Ye ◽  
Ying Jiang
Keyword(s):  
Ball Milling ◽  
Exchange Coupling ◽  
Maximum Energy ◽  
Effective Exchange ◽  
Energy Products

Research on Magnetic Properties of Nd2Fe14B/α-Fe/Nd2Fe14B Exchange-Coupled Trilayer Films

2011 ◽  
Vol 84-85 ◽  
pp. 567-571
Author(s):  
Min Gang Zhang ◽  
Li Li Yang ◽  
Yi Chao Zhao ◽  
Jia Zhang ◽  
Gang Sun
Keyword(s):  
Exchange Coupling ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Maximum Energy ◽  
Soft Magnetic ◽  
Coupling Region ◽  
Magnetic Hysteresis Loops ◽  
Complete Exchange ◽  
Energy Products ◽  
The Relationship

The magnetic hysteresis loops of Nd2Fe14B/α-Fe/Nd2Fe14B exchange-coupling trilayer film are simulated by micromagnetic theory, and the relationship between remanence, coercivity, energy products and soft magnetic thickness are discussed in detail. The results show that the hysteresis loops is rectangle and the trilayer films are in complete exchange-coupling region when the soft magnetic thickness is below the critical point(5nm); With the increase of the soft magnetic thickness, the coercivity of the trilayer films decreases monotonically. Maximum energy products are obtained when the soft magnetic thickness is 5nm.

Exchange Coupling Interaction in L10-FePd/α-Fe Nanocomposite Magnets with Large Maximum Energy Products

ACS Nano ◽  
2011 ◽  
Vol 5 (4) ◽  
pp. 2806-2814 ◽  
Author(s):  
Noritsugu Sakuma ◽  
Tsubasa Ohshima ◽  
Tetsuya Shoji ◽  
Yoshihito Suzuki ◽  
Ryota Sato ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Maximum Energy ◽  
Coupling Interaction ◽  
Nanocomposite Magnets ◽  
Exchange Coupling Interaction ◽  
Large Maximum ◽  
Energy Products

Influence of Additional Micro-Sized Particles of Dy–Nd–Cu–Al on Magnetic Properties of Sintered Nd–Fe–B Magnets

2021 ◽  
Vol 21 (4) ◽  
pp. 2558-2562
Author(s):  
Pham Thi Thanh ◽  
Dinh Thi Kim Oanh ◽  
Nguyen Hai Yen ◽  
Nguyen Huy Dan
Keyword(s):  
Magnetic Properties ◽  
Ball Milling ◽  
Weight Fraction ◽  
Maximum Energy ◽  
Vacuum Sintering ◽  
Magnetic Parameters ◽  
Maximum Value ◽  
High Maximum ◽  
Milling Method ◽  
Energy Products

In this work, we investigated the influence of concentration of the additional micro-sized particles of Dy40Nd30Al30 and Nd40Cu30Al30 on magnetic properties of the sintered Nd16.5Fe77B6.5 magnets. The additional particles with size in the range of 1–3 μm were prepared by ball milling method and then mixed into micrometer Nd16.5Fe77B6.5 master powder with different weight fractions before magnetic anisotropic pressing, vacuum sintering and annealing. The results show that the coercivity of the sintered Nd–Fe–B magnets can be improved considerably by introducing additional particles to the grain boundaries. The improvement of the coercivity Hc of the magnets is clearly dependent on the composition and concentration of the additional microparticles. The Hc increases linearly from 8.5 kOe to 17 kOe with increasing the weight fraction of the Dy40Nd30Al30 microparticles from 0 to 5%. Meanwhile, the coercivity of the magnet reaches a maximum value of 11.7 kOe with 4 wt% addition of Nd40Cu30Al30. The quite high maximum energy products, (BH)max > 30 MGOe, were also obtained for the magnets added with the microparticles. The obtained hard magnetic parameters of the magnets can be applied in practice.

A Study on The Phase Transformation and Exchange-Coupling of (Nd0 95La0 05)9 5FebalCo5Nb2B10.5 Nanocomposites

1999 ◽  
Vol 577 ◽  
Author(s):  
Q. Chen ◽  
B. M. Ma ◽  
B. Lu ◽  
M. Q. Huang ◽  
D. E. Laughlin
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Phase Transformation ◽  
Thermal Treatment ◽  
Grain Growth ◽  
Exchange Coupling ◽  
Phase Distribution ◽  
Maximum Energy ◽  
Treatment Temperature ◽  
Phase Identification

ABSTRACTThe phase transformation and the exchange coupling in (Ndo095Lao005)9.5FebaICOsNb 2BI05 have been investigated. Nanocomposites were obtained by treating amorphous precursors at temperatures ranging from 650TC to 9500C for 10 minutes. The magnetic properties were characterized via the vibrating sample magnetometer (VSM). X-ray diffraction (XRD), thermomagnetic analysis (TMA), and transmission electron microscopy (TEM) were used to perform phase identification, measure grain size, and analyze phase distribution. The strength of the exchange coupling between the magnetically hard and soft phases in the corresponding nanocomposite was analyzed via the AM-versus-H plot. It was found that the remanence (Br), coercivity (Hci), and maximum energy product (BHmax) obtained were affected by the magnetic phases present as well as the grain size of constituent phases and their distribution. The optimal magnetic performance, BHm, occurred between 700°C to 750°C, where the crystallization has completed without excessive grain growth. TMA and TEM indicated that the system was composed of three phases at this point, Nd2(Fe Co) 14B, ca-Fe, and Fe3B. The exchange coupling interaction among these phases was consistently described via the AM-versus-H plot up to 750°C. The Br, Hci, and BHmax degraded severely when the thermal treatment temperature increased from 750°C. This degradation may be attributed to the grain growth of the main phases, from 45 to 68nm, and the development of precipitates, which grew from 5nm at 750°C to 12nm at 850°C. Moreover, the amount of the precipitates was found to increase with the thermal treatment temperatures. The precipitates, presumably borides, may cause a decrease in the amount of the a-Fe and Fe 3B and result in a redistribution of the Co in the nanocomposites. The increase of the Co content in the Nd 2(Fe Co) 14B may explain the increase of its Curie temperature with the thermal treatment temperatures. In this paper, we examine the impacts of these factors on the magnetic properties of (Ndo 95Lao 05)9 5FebaICosNb2B10.5 nanocomposite.

scholarly journals Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1308 ◽  
Author(s):  
Arnab Chakraborty ◽  
Răzvan Hirian ◽  
Gregor Kapun ◽  
Viorel Pop
Keyword(s):  
Heat Treatment ◽  
Exchange Coupling ◽  
Permanent Magnets ◽  
High Energy ◽  
Raw Material ◽  
Energy Ball ◽  
Hydrogen Decrepitation ◽  
Energy Products ◽  
First Time ◽  
Recycled Material

Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.

Effective exchange coupling in alternating-chains of a π-extended 1,2,4-benzotriazin-4-yl

2014 ◽  
Vol 38 (3) ◽  
pp. 949-954 ◽  
Author(s):  
Christos P. Constantinides ◽  
Andrey A. Berezin ◽  
Maria Manoli ◽  
Gregory M. Leitus ◽  
Michael Bendikov ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Radical Pairs ◽  
Effective Exchange

Air stable 1,3,7-triphenyl-1,4-dihydrothiazolo[5′,4′:4,5]benzo[1,2-e][1,2,4]triazin-4-yl packs in 1D π stacks made of radical pairs with alternate short and long interplanar distances.

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.

Nanocrystalline and Nanostructured High-Performance Permanent Magnets

2001 ◽  
Vol 674 ◽  
Author(s):  
D. Goll ◽  
W. Sigle ◽  
G.C. Hadjipanayis ◽  
H. Kronmüller
Keyword(s):  
Magnetic Properties ◽  
High Performance ◽  
Permanent Magnets ◽  
Maximum Energy ◽  
High Quality ◽  
Hardening Mechanism ◽  
Temperature Dependences ◽  
Complex Correlation ◽  
Energy Products

ABSTRACTThe rather complex correlation between the microstructure and the magnetic properties is demonstrated for two types of high-quality RE-TM permanent magnets (pms), namely nanocrystalline RE2Fe14B (RE = Nd,Pr) and nanostructured Sm2(Co,Cu,Fe,Zr)17 pms. The detailed analysis of this correlation for both pm materials leads to a quantitative comprehension of the hardening mechanism enabling the optimization of their magnetic properties and temperature dependences. In the case of RE2Fe14B, isotropic bonded pms are fabricated showing maximum energy products in the order of 90 kJ/m3. In the case of Sm2(Co,Cu,Fe,Zr)17, magnets with excellent high-temperature magnetic properties are tailored. Hereby, the investigations in addition provide important clues to the evolution of the characteristic microstructural and magnetic properties and to the role of the involved elements.

Role of diffused Co atoms in improving effective exchange coupling inSm−Co∕Fespring magnets

2007 ◽  
Vol 75 (10) ◽  
Author(s):  
Y. Choi ◽  
J. S. Jiang ◽  
Y. Ding ◽  
R. A. Rosenberg ◽  
J. E. Pearson ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Effective Exchange
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