A nanocrystalline Sm–Co compound for high-temperature permanent magnets

Zhang, Zhexu; Song, Xiaoyan; Qiao, Yinkai; Xu, Weiwei; Zhang, Jiuxing; Seyring, Martin; Rettenmayr, Markus

doi:10.1039/c3nr34134h

Cited by 31 publications

(9 citation statements)

References 30 publications

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“…Sm-Co intermetallic compounds are known to be the best performing permanent magnets in a high temperature range. [1][2][3] Compared with the equilibrium phases Sm 2 Co 17 (2:17) and SmCo 5 (1:5), the metastable phase SmCo 7 (1:7) shows higher Curie temperature together with strong uniaxial magnetocrystalline anisotropy. 4 Thus, alloys with the stabilized 1:7 phase are the prime candidates for advanced permanent magnets that are to be applied in a high temperature range.…”

Section: Introductionmentioning

confidence: 99%

Concurrent ordering and phase transformation in SmCo₇ nanograins

et al. 2015

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Sm-Co alloys with the stabilized SmCo7 phase are most prominent candidates for advanced high temperature permanent magnets, where the stabilization of the SmCo7 phase can be effectuated by nanostructuring. The complex concurrent processes of ordering and phase transformation in a SmCo7 nanograin are characterized on the atomic scale. For the first time early stages of the phase transformation are made visible by highlighting specific superstructures in single nanograins using Fourier reconstruction of high-resolution transmission electron microscopy images. The superstructures are only detectable and can only be distinguished in specific crystallographic orientations. The evolution of the atom arrangement in the crystal structures is demonstrated for the concurrent ordering process and phase transformation. During decomposition of the metastable SmCo7 phase, the hexagonal Sm2Co17 superstructure (2:17H) forms at first as a precursor of the rhombohedral Sm2Co17 superstructure (2:17R) – this can only be detected by analysis of individual grains and has not been described so far. By extensive crystallographic analysis of individual nanograins, a distinct correlation between the fraction of the superstructure phases and the grain size is found, showing directly and unambiguously the grain size dependence of the phase transformation in the nanocrystalline alloy, a phenomenon that so far has only been shown indirectly using volume averaging methods.

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Section: Introductionmentioning

confidence: 99%

Concurrent ordering and phase transformation in SmCo₇ nanograins

et al. 2015

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“…Metastable phases in the Sm-Co system, such as SmCo 7 , Sm 5 Co 19 and SmCo 9.8 , have been successfully prepared by some non-equilibrium techniques developed in recent years [47,61,62,82,83] . The metastable phase dominated alloys can have special and outstanding functional properties, which may be difficult to obtain in equilibrium phased alloys.…”

Section: Metastable Phasesmentioning

confidence: 99%

“…In this review, we provide an overview of modeling studies of phase stability in alloys, including theories, models and methods. The Sm-Co alloy system, as one of the two most famous rare-earth permanent magnetic materials families [45] , is taken as an example, with the consideration that this system is rich in various stable and metastable phases under the conditions of binary compositions [46][47][48][49][50][51][52][53] . Efforts are made to introduce the progress in the studies of the phase stability and transformation behavior of Sm-Cobased alloys, in which the development of the research approaches from the traditional CMS methods to strategies based on the materials informatics is particularly demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Modelling of phase stability: integrating computational materials science and materials informatics

Song¹,

Kai²,

Liu³

et al. 2021

JMI

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With rapid developments in big data and artificial intelligence technologies, materials informatics has become a new paradigm of materials science and engineering. In this review, the progress of modeling studies of phase stability in alloys is presented, with particular attention given to the development of the paradigm from traditional computational materials science (CMS) to materials informatics. The features of CMS models for phase stability studies are compared with those of data-driven approaches. The advantages of data-driven modeling in the framework of materials informatics are revealed. The approaches for developing interpretable machine learning, which has been mainly integrated with the developed CMS models and material science theories, are also discussed. Finally, the prospects for data-driven materials design based on the stability control of the dominant phases with regards to performance are proposed.

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“…either by altering the processing parameters or by the addition of some alloying element. According to Zhexu Zhang et al, 1) for a singlephase binary alloy of SmCo, by far the maximum coercivity is 36.76 kOe, which was achieved in case of Sm 5 Co 19 phase. Though, Lei Fang et al, 2) demonstrated that dry milling of SmCo5 yielded 41 kOe coercivity.…”

Section: Introductionmentioning

confidence: 99%

Effect of Microstructure on the Coercivity of SmCo<sub>5</sub> Intermetallic Compound

Akhtar

Khan

Khan³

et al. 2020

Mater. Trans.

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SmCo 5 is well known for its high coercive properties. This property helped the compound to become stable even at high temperatures. A lot of efforts had been made to improve this important property but so far only a few percentages of the theoretical coercivity values were achieved. Improving processing parameters or doping by other alloying elements are two popular ways to manipulate the properties of SmCo 5 . In this research work, the cooling temperature of the indigenously developed water-cooled copper mold was manipulated to control the solidifying peritectic structure. The obtained casting was milled to powder and the final sintered product was produced. It was noted that high coercive values i.e. 32.9 kOe was achieved at low water inlet temperature. The results were interpreted by using a scanning electron microscope (SEM), Differential thermal analysis and X-Ray diffraction analysis. SEM results revealed peritectic nano-structure in SmCo 5 compounds. These nano-structures seem helped to improve the coercivity of SmCo 5 .

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A nanocrystalline Sm–Co compound for high-temperature permanent magnets

Cited by 31 publications

References 30 publications

Concurrent ordering and phase transformation in SmCo₇ nanograins

Concurrent ordering and phase transformation in SmCo₇ nanograins

Modelling of phase stability: integrating computational materials science and materials informatics

Effect of Microstructure on the Coercivity of SmCo<sub>5</sub> Intermetallic Compound

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A nanocrystalline Sm–Co compound for high-temperature permanent magnets

Cited by 31 publications

References 30 publications

Concurrent ordering and phase transformation in SmCo7 nanograins

Concurrent ordering and phase transformation in SmCo7 nanograins

Modelling of phase stability: integrating computational materials science and materials informatics

Effect of Microstructure on the Coercivity of SmCo<sub>5</sub> Intermetallic Compound

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Concurrent ordering and phase transformation in SmCo₇ nanograins

Concurrent ordering and phase transformation in SmCo₇ nanograins