Thanh Pham Thi, Oanh Dinh Thi Kim, Yen Nguyen Hai, Dan Nguyen Huy
Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Ha Noi, 100000, Viet Nam.
Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Ha Noi, 100000, Viet Nam.
J Nanosci Nanotechnol. 2021 Apr 1;21(4):2558-2562. doi: 10.1166/jnn.2021.19100.
In this work, we investigated the influence of concentration of the additional micro-sized particles of DyNdAl and NdCuAl on magnetic properties of the sintered NdFeB magnets. The additional particles with size in the range of 1-3 m were prepared by ball milling method and then mixed into micrometer NdFeB master powder with different weight fractions before magnetic anisotropic pressing, vacuum sintering and annealing. The results show that the coercivity of the sintered Nd-Fe-B magnets can be improved considerably by introducing additional particles to the grain boundaries. The improvement of the coercivity H of the magnets is clearly dependent on the composition and concentration of the additional microparticles. The H increases linearly from 8.5 kOe to 17 kOe with increasing the weight fraction of the DyNdAl microparticles from 0 to 5%. Meanwhile, the coercivity of the magnet reaches a maximum value of 11.7 kOe with 4 wt% addition of NdCuAl. The quite high maximum energy products, (BH) > MGOe, were also obtained for the magnets added with the microparticles. The obtained hard magnetic parameters of the magnets can be applied in practice.
在本工作中，我们研究了DyNdAl和NdCuAl的额外微米级颗粒浓度对烧结钕铁硼磁体磁性能的影响。通过球磨法制备尺寸在1 - 3微米范围内的额外颗粒，然后在磁各向异性压制、真空烧结和退火之前，将其以不同重量分数混入微米级钕铁硼母粉中。结果表明，通过在晶界引入额外颗粒，烧结钕铁硼磁体的矫顽力可得到显著提高。磁体矫顽力H的提高明显取决于额外微粒的组成和浓度。随着DyNdAl微粒重量分数从0增加到5%，H从8.5 kOe线性增加到17 kOe。同时，添加4 wt%的NdCuAl时，磁体的矫顽力达到最大值11.7 kOe。对于添加了微粒的磁体，还获得了相当高的最大磁能积，(BH) > MGOe。所获得的磁体硬磁参数可实际应用。
