Sm
                  2
                (Co,Fe,Cu,Zr)
                  17
           magnets for use at temperature ⩾400 °C

Chen, Christina; Walmer, M.H.; Liu, S.; Kuhl, Ellen; Simon, Gerard

doi:10.1063/1.367937

Cited by 109 publications

(36 citation statements)

References 7 publications

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“…Similarly, magnets which have not been heat treated optimally (Ta too low, t a too short) also show smaller cell sizes and therefore less Cu in the cell walls. In contrast, in the Cu-rich case the equilibrium is completely shifted to the left leading to a entirely different temperature behaviour of the wall energies -ý"5 and -2 y: 7 and therefore to a strongly negative temperature coefficient of the coercivity according to eq. (2) and eq.(3).…”

Section: Coercivity Mechanismmentioning

confidence: 99%

“…For a further improvement of the performance of polymer bonded magnets and the hightemperature magnetic properties, especially the temperature stability of the coercivity, the most important prerequisite for both hard magnetic materials is the detailed analysis of the hardening mechanisms and in the case of Sm 2 (Co,Cu,Fe,Zr)1 7 additionally of its formation. It is nowadays generally accepted that in RE 2 Fe1 4 B based materials the nucleation mechanism governs the coercivity, whereas in Sm 2 Co1 7 based materials domain wall pinning processes are dominant.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, nanocrystalline magnetic materials of this system have opened a new class of pm materials which are optimally suitable for high-performance polymer bonded magnets. Pms which supply the highest (BII)mnx values at elevated temperatures (beyond which RE2Fe, 4 B is no longer viable) are based on the quintary system Sm 2 (Co,Cu,Fe,Zr)1 7 [5]., With such magnets coercivities as large as I T can be realized even at 500'C which makes them suitable for high temperatures [6,7].…”

Section: Introductionmentioning

confidence: 99%

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Nanocrystalline and Nanostructured High-Performance Permanent Magnets

2001

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The rather complex correlation between the microstructure and the magnetic properties is demonstrated for two types of high-quality RE-TM permanent magnets (pins), namely nanocrystalline RE 2 Fe, 4 B (RE = Nd,Pr) and nanostructured Sm 2 (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 RE 2 Fe, 4 B, isotropic bonded pms are fabricated showing maximum energy products in the order of 90 kJ/m 3 . In the case of Sm 2 (Co,Cu,Fe,Zr)1 7 , magnets with excellent hightemperature 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.

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Section: Coercivity Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanocrystalline and Nanostructured High-Performance Permanent Magnets

2001

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“…Some studies [17,18] suggested that the high temperature performance of SmCo 2:17 magnets can be improved by decreasing the Fe content. Our results show that for some compositions the addition of a certain amount of Fe is necessary to develop a uniform cellular microstructure with a larger cell size and thus a high coercivity.…”

Section: Effect Of Fementioning

confidence: 99%

Effect of Composition and Processing on the Microstructure and Magnetic Properties of 2:17 High Temperature Magnets

Tang

Zhang

Goll³

et al. 2001

MRS Proc.

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A comprehensive and systematic study has been made on Sm(CobalFevCuyZrx)zmagnets to completely understand the effects of composition and processing on their magnetic properties. The homogenized Sm(Co,Fe,Cu,Zr)z magnets have a featureless microstructure. A cellular/lamellar microstructure develops after 2-3 hours of aging at 800-850°C, but the coercivity increases only after a subsequent slow cooling to 400°C. During cooling, diffusion takes place and Cu is concentrated in the 1:5 cell boundaries and Fe in the 2:17R cells. This dilutes the magnetic properties of the 1:5 phase and causes domain wall pinning/nucleation at the cell boundaries. Higher ratio z leads to larger cells as expected due to the larger amount of the 2:17 phase. For a fixed Cu content, this translates to a larger amount of Cu in the 1:5 cell boundaries, and therefore, to a higher coercivity. Magnets without Cu but with Zr have a lamellar and a cellular like microstructure. In Zr free samples, however, a larger amount of Cu is needed to form the cellular microstructure. This cellular microstructure is unstable with prolonged isothermal aging. A uniform and stable cellular/lamellar microstructure is only observed in alloys containing both Cu and Zr. A higher aging temperature Tag leads to larger cells and higher coercivity as explained above. The results of all these studies clearly show that the amount of Cu in the 1:5 cell boundaries controls both the coercivity and its temperature dependence leading to positive and negative temperature coefficients of coercivity in low and high Cu content alloys, respectively.

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“…9) In this study, the use of the glass slag method in the extraction of Sm from the Sm-Co magnets, which have become renewed interests as the high temperature permanent magnets. 10,11) The degree of the extraction of Sm from the Sm-Co alloys is evaluated by chemical and microstructural analyses of the Sm-Co alloys processed by the glass slag method.…”

Section: Introductionmentioning

confidence: 99%

The Extraction of Sm from Sm-Co alloys by the Glass Slag Method

et al. 2003

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The use of the glass slag method in the extraction of Sm from Sm-Co alloys was studied. The magnetic SmCo 5 phase decomposed into Sm oxide phase and Co phases by the glass slag method. The Sm oxide phase was extracted by the surrounding molten glass slag materials in the glass slag method. The resultant alloys consisted of neither SmCo 5 phase nor Sm oxide phase. In the glass slag method, the Sm-Co alloys were separated into Sm-containing glass slag material and a Co-B alloy. The glass slag method was suitable for the extraction of samarium from the Sm-Co alloys as was the case for the extraction of neodymium from the Nd-Fe-B alloys.

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Sm 2 (Co,Fe,Cu,Zr) 17 magnets for use at temperature ⩾400 °C

Cited by 109 publications

References 7 publications

Nanocrystalline and Nanostructured High-Performance Permanent Magnets

Nanocrystalline and Nanostructured High-Performance Permanent Magnets

Effect of Composition and Processing on the Microstructure and Magnetic Properties of 2:17 High Temperature Magnets

The Extraction of Sm from Sm-Co alloys by the Glass Slag Method

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