High temperature 2:17 magnets: relationship of magnetic properties to microstructure and processing

Hadjipanayis, G. C.; Tang, Wei; Zhang, Y.; Chui, S. T.; Liu, J.F.; Chen, C.; Kronmüller, H.

doi:10.1109/20.908808

Cited by 168 publications

(97 citation statements)

References 23 publications

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“…Recent reports have revealed that the Cu enrichment in the cell boundary phase (SmCo 5 phase) reduces the anisotropy field of the SmCo 5 phase in comparison with that of the Sm 2 Co 17 phase; this eventually results in the high coercivity in Sm(Co,Fe,Cu,Zr) z magnets. 2,13) On the other hand, we have reported that by step aging, the Cu atoms are segregated into the cell boundary phases and the distribution of lines of magnetic flux fluctuates considerably. Some of the experimental results have been published in the previous paper.…”

Section: Introductionmentioning

confidence: 99%

“…1,2) Their magnetic properties depend sensitively on the microstructure and magnetic domain structure controlled by the sophisticated and lengthy heat treatments. [3][4][5] For example, by employing the step-aging method, the coercivity and maximum energy product increased drastically from 33 to 749 kA/m and from 20 to 192 kJ/m 3 , respectively, while there was a slight decrease in the remanence from 1.1 to 1.0 T. The high coercivity of Sm(Co,Fe,Cu,Zr) z magnets can be fundamentally explained by the pinning of the domain wall to the nanoscaled cell boundary precipitated in the cellular structure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructures and Magnetic Domain Structures of Sintered Sm(Co0.720Fe0.200Cu0.055Zr0.025)7.5 Permanent Magnet Studied by Transmission Electron Microscopy

et al. 2006

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Microstructures and magnetic domain structures of precipitation-hardened Sm(Co 0:720 Fe 0:200 Cu 0:055 Zr 0:025 ) 7:5 permanent magnets obtained by various heat treatments are investigated by transmission electron microscopy (TEM). It is found that Cu atoms gradually segregate into SmCo 5 phase with the increase in aging time. The domain walls in the solution-treated, 6-h isothermal-aged magnets are straight, while those in the step-aged magnet are zigzag shaped along the cell boundaries of the SmCo 5 phases (1:5 H phases). In the demagnetized state of the step-aged magnet, it is found that the domain wall is located almost on the 1:5 H cell boundary phase containing Cu atoms, where the distribution of lines of magnetic flux strongly deviates from the axis of easy magnetization, particularly near the zigzag domain wall, and the lines of magnetic flux flow symmetrically along the center of the 1:5 H cell boundary phase. In the remanent state of the step-aged magnet, it is confirmed that domain walls are strongly pinned almost to the 1:5 H cell boundary phase containing Cu atoms, eventually resulting in a high coercivity in a Sm

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructures and Magnetic Domain Structures of Sintered Sm(Co0.720Fe0.200Cu0.055Zr0.025)7.5 Permanent Magnet Studied by Transmission Electron Microscopy

et al. 2006

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“…4 that there are also temperatures at which . In this case, (3) predicts , but in reality there are chemical concentration fluctuations [10], so that the material is never truly homogeneous.…”

Section: Origin Of the Positive Temperature Coefficientmentioning

confidence: 99%

Coercivity of titanium-substituted high-temperature permanent magnets

2001

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Abstract-The temperature dependence of the coercivity of Sm-Co based magnets is investigated by magnetization measurements and model calculations. The Zr-free titanium-substituted Sm-Co material exhibits a positive temperature coefficient of the coercivity (TCC) above room temperature, a reasonable hysteresis-loop shape, and an appreciable coercivity of 12.3 kOe at 500 C for the nominal composition Sm(Co 6 2 Cu 0 8 Ti 0 3 ). The samples were produced by heat-treating the disordered 1 : 5 alloy commonly referred to as the TbCu 7 (or 1 : 7) phase. X-ray diffraction analysis shows that, upon annealing at 1165 C, the starting material segregates into more-or-less stoichiometric 1 : 5 and 2 : 17 phases. The TCC is explained by taking into account that two-phase Sm-Co magnets are of the pinning type, that is the coercivity is realized by capturing (or repelling) domain walls at 1 : 5/2 : 17 phase boundaries. Starting from a planar-defect approach, the TCC is modeled as a function of the anisotropy constants of the involved phases. The present approach yields a fair agreement between theory and experiment, and explains the existence of a coercivity maximum in terms of the Cu concentration.Index Terms-Domain wall pinning, high-temperature permanent magnets, Sm-Co based permanent magnets, temperature dependence of coercivity.

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“…A small amount of the third element (i.e. Cu, Zr, Ti, Hf, and Si) can stabilize the Sm-Co phase with the TbCu 7 -type structure [6][7][8][9][10]. Hence, Cu and Zr were doped as the third elements to stabilize the SmCo 7 -type phase in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…However, the Sm 2 Co 17 -type alloys have shortcomings of a low intrinsic coercivity and low operating temperature [8] whereas the disadvantages of the SmCo 5 -type alloys are their relatively lower Curie temperature and magnetic moment [9]. In comparison, the Sm(Co,M) 7 (M = stabilizing element) compounds with the TbCu 7 -type structure (space group P6/mmm) possess a higher predicted Curie temperature, a high magnetic anisotropy field, and a low intrinsic coercivity temperature coefficient [10].…”

Section: Introductionmentioning

confidence: 99%

Study on the Magnetic Characteristics of Anisotropic SmCo₇-type Alloys Synthesized by High-energy Surfactant-assisted Ball Milling

Yu¹,

Zhang²,

Shi³

et al. 2014

Journal of Magnetics

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An effective process was employed for synthesizing anisotropic magnetic SmCo 7 -type alloy flakes with high coercivity, which is highly desirable for many applications. The highest coercivity of 16.3 kOe corresponds to a typical flake thickness of 200 nm for the 3-h ball-milled sample. The anisotropy field was calculated by measuring the parallel and perpendicular directions to the easy magnetization direction of the powders. The anisotropy field decreased with the increase of the ball milling time, thus indicating that the decrease of coercivity was mainly caused by the reduction of the anisotropy field. Microstructure analysis indicated that the morphology, grain size, and anisotropy field of these samples have a great influence on the magnetic properties.

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High temperature 2:17 magnets: relationship of magnetic properties to microstructure and processing

Cited by 168 publications

References 23 publications

Microstructures and Magnetic Domain Structures of Sintered Sm(Co<SUB>0.720</SUB>Fe<SUB>0.200</SUB>Cu<SUB>0.055</SUB>Zr<SUB>0.025</SUB>)<SUB>7.5</SUB> Permanent Magnet Studied by Transmission Electron Microscopy

Microstructures and Magnetic Domain Structures of Sintered Sm(Co<SUB>0.720</SUB>Fe<SUB>0.200</SUB>Cu<SUB>0.055</SUB>Zr<SUB>0.025</SUB>)<SUB>7.5</SUB> Permanent Magnet Studied by Transmission Electron Microscopy

Coercivity of titanium-substituted high-temperature permanent magnets

Study on the Magnetic Characteristics of Anisotropic SmCo₇-type Alloys Synthesized by High-energy Surfactant-assisted Ball Milling

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High temperature 2:17 magnets: relationship of magnetic properties to microstructure and processing

Cited by 168 publications

References 23 publications

Microstructures and Magnetic Domain Structures of Sintered Sm(Co<SUB>0.720</SUB>Fe<SUB>0.200</SUB>Cu<SUB>0.055</SUB>Zr<SUB>0.025</SUB>)<SUB>7.5</SUB> Permanent Magnet Studied by Transmission Electron Microscopy

Microstructures and Magnetic Domain Structures of Sintered Sm(Co<SUB>0.720</SUB>Fe<SUB>0.200</SUB>Cu<SUB>0.055</SUB>Zr<SUB>0.025</SUB>)<SUB>7.5</SUB> Permanent Magnet Studied by Transmission Electron Microscopy

Coercivity of titanium-substituted high-temperature permanent magnets

Study on the Magnetic Characteristics of Anisotropic SmCo7-type Alloys Synthesized by High-energy Surfactant-assisted Ball Milling

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Product

Resources

About

Study on the Magnetic Characteristics of Anisotropic SmCo₇-type Alloys Synthesized by High-energy Surfactant-assisted Ball Milling