Morphology and magnetic properties of Sm2Co7/α-Fe nanocomposite magnets produced by high energy ball milling and spark plasma sintering

Abstract

In this article, the Sm2Co7/α-Fe nanocomposite magnets were prepared by high energy ball milling and spark plasma sintering method. The effect of soft phase content on the magnetic properties was studied. Up to 30 wt% α-Fe was added into Sm2Co7 matrix without the decrease of remanence. Optimal energy product (BH)max of 9.2MGOe was obtained with 20 wt% α-Fe. TEM observation shows that the grain size of α-Fe is 20–50 nm which ensures a good coupling effect between soft and hard phase. One more thing needs to be mentioned is that there exists inter-diffusion between Sm–Co phase and α-Fe phase. Moreover, our results can also illustrate that the Sm2Co7/α-Fe nanocomposite magnets are able to acquire better magnetic properties than the SmCo5/α-Fe magnets prepared by the same process due to the large domain width of Sm2Co7 phase.