C.Y. Li1)
,
H.Q. Yuan2)
,
F.X. Meng3) and Z. Zhou4) 1) Institute of Liaoning Technology
,
Jinzhou 121001
,
China 2) Northeastern University
,
Shenyang 10006
,
China 3) Shenyang University
,
Shenyang 110044
,
China 4) Xincheng Rare Earth Magnetostrictive Materials Ltd.
,
Dashiqiao 115100
,
China
金属学报(英文版)
The physical modelanditsequivalentcircuitoftestapparatusissetup by meansofimpedanceanalysis method. The magnetostriction coefficient, magnetomechanicalcoupling coefficient,frequency and anti- frequency of TbxDy1 - xFe2 - z(0 27 ≤x ≤0 3 ,0 ≤z ≤0 1) rod are measured. Somecoupling problems with mechanicalstress and electromagnetic field such as flux leakage in magnetic path are discussed. The comparing calculated with tested resultsshowsthe accuracyof measurementand thesimplification of model.
关键词:
magnetostriction material
,
null
,
null
Journal of Physics D-Applied Physics
A comprehensive review is given of recent advances in the study of metastable phases in rare-earth permanent magnets. The relations between the structures of the metastable and equilibrium phases and the transformations from the former to the latter are discussed. The formation of the phases is found to depend on the difference between the symmetries of the metastable and equilibrium phases. The magnetic properties of the metastable-phase rare-earth permanent magnets synthesized by various processes, such as mechanical alloying, mechanical milling, rapid quenching, hydrogenation, disproportionation, desorption and recombination, solid-state reaction, solid-gas reaction, self-flux and sputtering, are compared. The main conclusion of this article is that searching for new metastable phases with high magnetic performance will be one of the most active directions in the research on rare-earth permanent magnets.
关键词:
fe-c alloys;disproportionation-desorption-recombination;solidified;sm-fe;r = nd;high-coercivity;magnetocrystalline anisotropy;intermetallic compounds;remanence enhancement;crystal-structure;high-performance
CHANG Ying
,
WANG Dapeng
,
LI Wei
,
PAN Wei
,
YU Xiaojun
,
QI Min
钢铁研究学报(英文版)
Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows: (1) Sm2TM17: Br=062 T, jHc=8037 kA/m, (BH)m=5897 kJ/m3, ρ=7 Ω·m; (2) NdFeB: Br=0485 T, jHc=76633 kA/m, (BH)m=3796 kJ/m3, ρ=9 Ω·m. The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.
关键词:
Sm2TM17;NdFeB;electrical insulation;eddy current
Solid State Communications
We have performed relativistic first-principles full-potential linearized augmented plane wave (FLAPW) calculation for rare earth palladium sulfide EuPd3S4 in the ferromagnetic and antiferromagnetic states. The density of 4f electrons of Eu is taken from a local-spin-density approximation self-interaction correction (LSDA-SIC) atomic calculation. EuPd3S4 is found to exhibit anti ferromagnetic ordering in its ground state. The charge, orbital, magnetic moment and spin ordering are explained with the electronic structure, the orbital-projected density of states and the total energy study. EuPd3S4 is found to be stable in the body-centered Type-I antiferromagnetic state, in agreement with experimental results. Different Eu states are found in antiferromagnetic ordering. The magnetic moments of different states obtained through spin-polarized calculation are also in good agreement with experimental results. The phenomena observed are explained by the orbital hybridization of Eu and Pd ions as compared with the free ions. (C) 2004 Elsevier Ltd. All rights reserved.
关键词:
FP_LAPW;LSDA-SIC;AFM;hybridization;bronzes;rpd3s4
自然科学进展﹒国际材料（英文）
Part of the results of the key project "Search for novel rare-earth functional materials" supported by the National Natural Science Foundation of China is reviewed. In combination with reports in literature, the effects of the third element M on the formation and stability of La-2(Co, M)(17), R(Fe, M)(12) and R-3(Fe, M)(29) intermetallic compounds are discussed by considering mixing enthalpy of M with rare-earth, Fe and Co, and atomic radius, electronegativity and electronic configurations, etc. It is concluded that the mixing enthalpy and atomic radius dominate the preferential sites and the minimum amount of M required to stabilize a structure, which ultimately affect the magnetic properties of a compound prominently. This review should provide some heuristic hints for exploiting novel rare-earth transition metal functional materials and for improving their performance.
关键词:
La-2 (Co, M)(17);R (Fe, M)(12);R-3(Fe, M)(29);crystal structure;magnetic properties;uniaxial magnetocrystalline anisotropy;subsolidus phase-relations;m;ternary-system;magnetic-properties;crystal-structure;neutron-diffraction;permanent-magnets;fe substitutions;nd;cr
稀土学报(英文版)
The microstructural characteristics of syntactic polycrystal in the calcium-rare earth fluorocarbonate minerals from Southwest China have been studied by means of selected area electron diffraction and high resolution electron microscopy(HREM). The complication of the heterogeneous fabric of the minerals have been revealed by HREM. The results show that the crystal structure of the minerals was formed by a disorder stacking of the unit layers of bast-naesite and synchisite in the calcium rare earth fluorocarbonate minerals along (c) over right arrow direction. The stacking fault and other crystal defects in the syntactic polycrystal have been discussed.
关键词:
rare earths;calcium rare earth fluorocarbonate mineral;syntactic;intergrowth;high resolution electron microscopy
Shaoxiong ZHOU
材料科学技术（英文）
The discovery of the first Fe-based ferromagnetic amorphous alloy in 1966 had made an impact on conventional magnetic materials because of its unique properties. Since then, a number of amorphous magnetic materials have been successfully developed and used in a wide variety of applications. A brief review of R & D activities on amorphous soft magnetic materials in China is given from the beginning to the present in a somewhat chronological order, followed by a brief introduction to their applications on electric and electronic industries. An analysis and a prospect of Chinese market of such amorphous materials are also presented.
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