High-performance multiphase Sm-Co-B alloys with coercivities up to 6.71 MA·m<sup>-1</sup>.

Wang, Shu; Sun, Ji-Bing; Chi, Xiang; Zhou, Mu-Jing; Ma, Hao-Yu; Zhang, Ying; Liu, Jian · Nat Commun · 2024

basic_science · Level V

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Abstract

SmCo<sub>4</sub>B-based alloys with high magnetocrystalline anisotropy are expected to be used as raw materials or constituent phases for new permanent magnets. In this work, we develop Sm(Co, Fe, Ni)<sub>4</sub>B alloys with excellent hard magnetic properties by tuning the contents of Fe, Co, and Ni. The addition of Fe enhances the amorphous formation ability of the as-spun ribbons, whereas Ni addition improves the structural stability of the crystalline phases. During annealing, the amorphous phase crystallizes into different Sm-Co-B phases in stages. A high coercivity of 5.68-6.71 MA·m<sup>-1</sup> is obtained in the annealed SmCo<sub>4-x-y</sub>Fe<sub>x</sub>Ni<sub>y</sub>B (x = 1.0-2.0, y = 0.8-1.0) ribbons composed of platelet-shaped and equiaxed grains in comparison with the coercivity of 2.89-5.18 MA·m<sup>-1</sup> in the x = 1.0-1.2 and y = 0-0.8 ribbons with equiaxed grains. Here, we show the strong correlations between the microstructure and magnetic properties and provide insights for the future development of high-performance SmCo<sub>4</sub>B-based magnets.