Microstructure and hard magnetic properties of nanocomposite Sm2Fe15Ga2Cx permanent magnets with an excess of Fe prepared directly by melt spinning

1998 ◽  
Vol 72 (9) ◽  
pp. 1110-1112 ◽  
Author(s):  
Zhao-hua Cheng ◽  
Jun-xian Zhang ◽  
Hui-qun Guo ◽  
J. van Lier ◽  
H. Kronmüller ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Hard Magnetic Properties

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.

The hard magnetic properties of nanocomposite Nd3.6Pr5.4Fe83Co3B5 ribbons prepared by melt spinning

2001 ◽  
Vol 304-306 ◽  
pp. 997-1000 ◽  
Author(s):  
Hong-Wei Zhang ◽  
Wen-Yong Zhang ◽  
A-Ru Yan ◽  
Zhi-Gang Sun ◽  
Bao-Gen Shen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Hard Magnetic Properties

High Magnetic Field Annealing of Mn-Ga Intermetallic Alloys

MRS Advances ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 227-233 ◽  
Author(s):  
Daniel R. Brown ◽  
Ke Han ◽  
Theo Siegrist ◽  
Tiglet Besara ◽  
Rongmei Niu
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Intermetallic Alloys ◽  
Nanostructured Composite ◽  
Refined Microstructure ◽  
Field Annealing ◽  
High Magnetic Moment ◽  
Hard Magnetic Properties

AbstractMn-Ga alloys have shown promising hard magnetic properties, even though these alloys contain no rare-earth metals. However, much work is needed before Mn-Ga alloys become viable permanent magnets for applications. One of the challenges is to enhance the remanence. One technique to improve this property is applying a magnetic field during the heat treatment process. Magnetic annealing can promote phase transformation of the phases with high magnetic moment. This results in an increased remanence. Bulk samples of Mn-Ga alloys were made by mechanically alloying in order to create a nanostructured composite, followed by heat treatments in the presence of a 31 T magnetic field. The heat treatment temperatures were kept low in order to keep the refined microstructure. All the alloys exhibit hard magnetic properties at room temperature with large coercivity. This work reports findings of magnetic field annealed Mn-Ga bulk that exhibit high coercivities up to 19.4 kOe and increased remanence of 50% over the binary system, achieving values up to 6.9 emu/g. This is the highest coercivity reported in bulk Mn-Ga samples.

scholarly journals Microstructure and Magnetic Properties of Ce14Fe78Co2B6 Nanopowders Prepared by Ball Milling at Low Temperature

2021 ◽  
Vol 7 (12) ◽  
pp. 160
Author(s):  
Marian Grigoras ◽  
Mihaela Lostun ◽  
Firuta Borza ◽  
Marieta Porcescu ◽  
George Stoian ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Ball Milling ◽  
Liquid Nitrogen ◽  
High Performance ◽  
Permanent Magnets ◽  
X Ray Diffraction ◽  
Hard Magnetic Properties ◽  
Uniform Particle Size ◽  
Microstructure And Magnetic Properties

Ce14Fe78Co2B6 nanopowders with hard-magnetic properties have been successfully prepared by ball milling at low temperatures in liquid nitrogen. The morphology, structure, and magnetic properties of Ce14Fe78Co2B6 powders have been investigated using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry, respectively. It was found that powder ball milling at low temperature in liquid nitrogen, has the advantage that the oxidation of powders is inhibited and the particles rapidly reach nanometric dimensions. In comparison to the Ce14Fe78Co2B6 powders prepared by ball milling at room temperature, the powders milled at low temperature present a more uniform particle size and no rare-earth oxides, which leads thus to remarkable magnetic properties. The nanocrystalline Ce14Fe78Co2B6 powders with optimum characteristics, prepared at low temperature, have the size of 153 nm or less, present a coercivity of 5.1 kOe, and a saturation magnetization of 113 emu/g after milling for 6 h at low temperature. Low temperature milling may become a promising technique for the fabrication of high performance powders used for permanent magnets preparation.

The hard magnetic properties of sintered NdFeB permanent magnets

1986 ◽  
Vol 118 (1) ◽  
pp. 167-172 ◽  
Author(s):  
R. Grössinger ◽  
R. Krewenka ◽  
R. Eibler ◽  
H.R. Kirchmayr ◽  
J. Ormerod ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Hard Magnetic Properties

ChemInform Abstract: Hard Magnetic Properties of Sintered Nd - Fe - B Permanent Magnets.

1986 ◽  
Vol 17 (31) ◽  
Author(s):  
R. GROESSINGER ◽  
R. KREWENKA ◽  
R. EIBLER ◽  
H. R. KIRCHMAYR ◽  
J. ORMEROD ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Hard Magnetic Properties

PrFeB Based Alloys Obtained by Melt Spinning for the Production of Permanent Magnets

2020 ◽  
Vol 1012 ◽  
pp. 314-318
Author(s):  
Marco Antonio Meira ◽  
Lucas Costa Moisés ◽  
Melissa Rohrig Martins da Silva ◽  
Susilene Real Janasi ◽  
Hidetoshi Takiishi
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Powder Metallurgy ◽  
Melt Spinning ◽  
Permanent Magnets ◽  
Wheel Speed ◽  
Essential Components ◽  
Intrinsic Coercivity ◽  
Sintered Permanent Magnets ◽  
Ejection Pressure

Rare earth permanent magnets are essential components in many fields of technology due to their excellent magnetic properties. There are some techniques used in the manufacture of permanent rare earth magnets: the powder metallurgy to obtain anisotropic HD sintered permanent magnets and the melt spinning and HDDR processes to obtain isotropic and anisotropic bonded permanent magnets. In this work, the influence of the melt spinning parameters on the microstructural and magnetic properties of the Pr14FebalCo16B6 alloy was studied. The alloy was melted and rapidly cooled at 9.9 x 105°C/s. The parameters used in the process were: wheel speed of 15 m/s and 20 m/s and ejection pressure of 25.3 kPa and 50.7 kPa. Ribbons and/or flakes of 30 μm thickness and width until 5 mm were obtained. Results show that the melt spinning alloys are nanocrystalline and that the parameters of the process influence the microstructure and their magnetic properties. Mean crystallite size up to 38.5 nm and intrinsic coercivity (iHc) up to 254 kA/m were obtained.

Effect of Preparation on Glass Formation and Magnetic Properties of Nd-Fe-Co-Al-B Alloys

2000 ◽  
Vol 644 ◽  
Author(s):  
G. Kumar ◽  
J. Eckert ◽  
L.Q. Xing ◽  
A. Güth ◽  
S. Roth ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Hysteresis Loops ◽  
Liquid Region ◽  
Atomic Order ◽  
Copper Mold ◽  
Mechanically Alloyed ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Hard Magnetic Properties

AbstractThe effect of alternative preparation methods (copper mold casting, melt spinning, and mechanical attrition) on amorphization and properties of Nd57Fe20Co5Al10B8 and Nd40Fe40Co5Al8B7 alloys has been investigated. For all differently prepared samples an amorphous phase is formed upon solidification or solid sate reaction. However, the samples prepared by different processing routes exhibit different transformation behavior in thermal analysis. The cast Nd57Fe20Co5Al10B8 rod exhibits crystallization at 790 K followed by melting at 810 K. Neither appreciable endothermic reaction due to a glass transition nor a supercooled liquid region have been observed. Mechanically alloyed powders and ball-milled prealloys reveal two exothermic DSC peaks in the range of 650-850 K. The J-H hysteresis loops of samples synthesized by different routes show that the unique atomic order responsible for hard magnetic properties can only be accessed at moderate cooling rate of the melt as realized in copper mold casting. Rapidly quenched ribbons, mechanically alloyed powders and ball-milled ingots do not show hard magnetic properties at room temperature. These results indicate that amorphous samples with different local atomic order can be prepared by different processing routes.

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