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Journal of Shanghai University（Natural Science Edition） ›› 2016, Vol. 22 ›› Issue (6): 710-718.doi: 10.3969/j.issn.1007-2861.2015.04.002

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Precipitation and growth of Nd2Fe14B/α-Fe during amorphous crystallized process and its magnetic properties

XUE Yun1, HOU Xueling1, HAN Ning2, LU Qianqian1, XU Hui1   

  1. 1. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;
    2. School of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
  • Received:2015-09-01 Online:2016-12-30 Published:2016-12-30

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Abstract:

The crystal structure, magnetic properties of the Nd9.5Fe76Co5Ti3B6.5  amorphous alloys annealed at different temperatures were investigated by X-ray diffraction(XRD), vibrating sample magnetometer (VSM), and differential scanning calorimeter (DSC). The results indicated that the Nd2Fe14B phase was precipitated prior to that of α-Fe phase from the amorphous matrix. Nd2Fe14B phase and α-Fe phase were precipitated at 600 and 680 ℃, respectively. α-Fe phase grain growed up more obviously than Nd2Fe14B phase with increasing annealing temperature. The grain sizes of α-Fe phase and Nd2Fe14B phase growed from 22.4 and 32.8 nm to 33.3 and 39.8 nm when they annealed at 690 to 700 ℃. When annealing at 690 ℃, there were strong exchange coupling effects between hard magnetic phase Nd2Fe14B with 32.8 nm and soft magnetic phase α-Fe with 22.4 nm. MeanwhileNd9.5Fe76Co5Ti3B6.5 alloy obtained the best magnetic properties with Br =0.88 T, Hci =523.76 kA/m, and (BH)max=100.01 kJ/m3.

Key words:  exchange coupling,  magnetic property ,  nanocomposites ,  NdFeB , crystallization