Effect of pre-alloy composition on the content of ferromagnetic phase of MnBi Melt spun ribbons


  • Nguyễn Xuân Trường Viện Khoa học vật liệu




MnBi hard magnetic material, MnBi LTP, spontaneous magnetization, MnBi melt – spun ribbons


The rare-earth-free hard magnetic material MnBi is potential for permanent magnet high-temperature applications. The ferromagnetic phase (noted as a Low Temperature Phase – LTP) MnBi has the moderate spontaneous magnetization Ms ~ 74 emu/g, the high magneto-crystalline energy Ka of ~ 0.9 MJ/m3, and the elevated Curie temperature Tc ~  360 oC and especially, the positive thermal coefficient of coercivity d(iHc)/dT > 0. Up to now, the MnBi powders with high LTP content and coercivity have usually been prepared using the melt-spinning technique. However, the large difference in the melting temperature Tm of the two constituents, Mn and Bi, and the strong reactivity of Bi with the copper-based wheel make the preparation of high-performance MnBi ribbons difficult. Using a novel approach, we overcame these difficulties and prepared the MnBi ribbons on the conventional commercial melt-spinning furnace ZGK-1. The influences of pre-alloy compositions on the magnetic properties of MnBi melt – spun ribbons will be discussed in detail.


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E. Adams, W. M. Hubbard, A. M. Syeles - A New Permanent Magnet from Powdered Manganese Bismuth, J. Appl. Phys. 23 (1952) 1207 - 1211.

Van Vuong Nguyen, Poudyal N., Xubo Liu, Liu J. P., Kewei Sun, Kramer M. J., Jun Cui - High-Performance MnBi Alloy Prepared Using Profiled Heat Treatment, IEEE Transactions on Magnetics 50 (12) (2014) 1-6.

J. M. D. Coey - New permanent magnets; manganese compounds, Journal of Physics: Condensed Matter 26 (6) (2014) 064211.

Y.-C. Chen, G. Gregori, A. Leineweber, F. Qu, C.-C. Chen, T. Tietze, H. Kronmüller, G. Schütz, E. Goering - Unique high-temperature performance of highly condensed MnBi permanent magnets, Scripta Materialia 107 (2015) 131-135.

C. Chinnasamy, M.M. Jasinski, A. Ulmer, W. Li, G. Hadjipanayis, J. Liu - Mn-Bi Magnetic Powders With High Coercivity and Magnetization at Room Temperature, IEEE Transactions on Magnetics 48 (11) (2012) 3641-3643.

J. Cui, J.-P. Choi, E. Polikarpov, M.E. Bowden, W. Xie, G. Li, Z. Nie, N. Zarkevich, M.J. Kramer, D. Johnson - Effect of composition and heat treatment on MnBi magnetic materials, Acta Materialia 79 (2014) 374-381.

A.M. Gabay, G.C. Hadjipanayis, J. Cui - Preparation of highly pure α-MnBi phase via melt-spinning, AIP Advances 8 (5) (2018) 056702.

K. Kanari, C. Sarafidis, M. Gjoka, D. Niarchos, O. Kalogirou - Processing of magnetically anisotropic MnBi particles by surfactant assisted ball milling, Journal of Magnetism and Magnetic Materials 426 (2017) 691-697.

C. Li, D. Guo, B. Shao, K. Li, B. Li, D. Chen - Effect of heat treatment and ball milling on MnBi magnetic materials, Materials Research Express 5 (1) (2018) 016104.

K.W. Moon, K. Jeon, M. Kang, Y. Byun, J.B. Kim, H. Kim, J. Kim - Synthesis and Magnetic Properties of MnBi(LTP) Magnets With High-Energy Product, IEEE Transactions on Magnetics 50 (11) (2014) 1-4.

P.-K. Nguyen, S. Jin, A.E. Berkowitz - MnBi particles with high energy density made by spark erosion, Journal of Applied Physics 115 (17) (2014) 17A756.

N. V. Rama Rao, A. M. Gabay, G. C. Hadjipanayis - Anisotropic fully dense MnBi permanent magnet with high energy product and high coercivity at elevated temperatures, J. Phys. D: Appl. Phys. 46 (2013) 062001 (062004pp).

N.V. Rama Rao, A.M. Gabay, X. Hu, G.C. Hadjipanayis - Fabrication of anisotropic MnBi nanoparticles by mechanochemical process, Journal of Alloys and Compounds 586 (2014) 349-352.

V.V. Ramakrishna, S. Kavita, R. Gautam, T. Ramesh, R. Gopalan - Investigation of structural and magnetic properties of Al and Cu doped MnBi alloy, Journal of Magnetism and Magnetic Materials 458 (2018) 23-29.

W. Xie, E. Polikarpov, J.-P. Choi, M.E. Bowden, K. Sun, J. Cui - Effect of ball milling and heat treatment process on MnBi powders magnetic properties, Journal of Alloys and Compounds 680 (2016) 1-5.

J.B. Yang, Y.B. Yang, X.G. Chen, X.B. Ma, J.Z. Han, Y.C. Yang, S. Guo, A.R. Yan, Q.Z. Huang, M.M. Wu, D.F. Chen - Anisotropic nanocrystalline MnBi with high coercivity at high temperature, Applied Physics Letters 99 (8) (2011) 082505.

Y. Yang, J.-W. Kim, P.-Z. Si, H.-D. Qian, Y. Shin, X. Wang, J. Park, O.L. Li, Q. Wu, H. Ge, C.-J. Choi - Effects of Ga-doping on the microstructure and magnetic properties of MnBi alloys, Journal of Alloys and Compounds 769 (2018) 813-816.

Y.B. Yang, X.G. Chen, R. Wu, J.Z. Wei, X.B. Ma, J.Z. Han, H.L. Du, S.Q. Liu, C.S. Wang, Y.C. Yang, Y. Zhang, J.B. Yang - Preparation and magnetic properties of MnBi, Journal of Applied Physics 111 (7) (2012) 07E312.

D.T. Zhang, W.T. Geng, M. Yue, W.Q. Liu, J.X. Zhang, J.A. Sundararajan, Y. Qiang - Crystal structure and magnetic properties of MnxBi100−x (x=48, 50, 55 and 60) compounds, Journal of Magnetism and Magnetic Materials 324 (11) (2012) 1887-1890.

P.Z. Si, Y. Yang, L.L. Yao, H.D. Qian, H.L. Ge, J. Park, K.C. Chung, C.J. Choi - Magnetic-field-enhanced reactive synthesis of MnBi from Mn nanoparticles, Journal of Magnetism and Magnetic Materials 476 (2019) 243-247.

H. Fang, J. Li, S. Shafeie, D. Hedlund, J. Cedervall, F. Ekström, C.P. Gomez, J. Bednarcik, P. Svedlindh, K. Gunnarsson, M. Sahlberg - Insights into phase transitions and magnetism of MnBi crystals synthesized from self-flux, Journal of Alloys and Compounds 781 (2019) 308-314.

Lakshmi C. S., Smith R. W. - Structural and magnetic properties of rapidly quenched Bi-Mn alloys, Materials Science and Engineering: A 133 (1991) 241-244.

Guo X., Altounian Z., Ström - Olsen J. O. - Formation of MnBi ferromagnetic phases through crystallization of the amorphous phase, Journal of Applied Physics 69 (8) (1991) 6067-6069.

Kang K., Lewis L. H., Moodenbaugh A. R. - Crystal structure and magnetic properties of MnBi–Bi nanocomposite, Journal of Applied Physics 97 (10) (2005) 10K302.

Guo X., Chen X., Altounian Z., Ström-Olsen J. O. - Magnetic properties of MnBi prepared by rapid solidification, Physical Review B 46 (22) (1992) 14578-14582.

Yang Y. B., Chen X. G., Guo S., Yan A. R., Huang Q. Z., Wu M. M., Chen D. F., Yang Y. C., Yang J. B. - Temperature dependences of structure and coercivity for melt-spun MnBi compound, Journal of Magnetism and Magnetic Materials 330 (2013) 106-110.

Saito Tetsuji, Nishimura Ryuji, Nishio-Hamane Daisuke - Magnetic properties of Mn–Bi melt-spun ribbons, Journal of Magnetism and Magnetic Materials 349 (2014) 9-14.

Kharel P., Shah V. R., Skomski R., Shield J. E., Sellmyer D. J. - Magnetism of MnBi-Based Nanomaterials, IEEE Transactions on Magnetics 49 (7) (2013) 3318-3321.

Nguyen Xuan Truong, Nguyen Van Vuong - Preparation and Magnetic Properties of MnBi Alloy and its Hybridization with NdFeB, Journal of Magnetics 20 (4) (2015) 336-341.

Nguyen Van Vuong, Nguyen Xuan Truong - Low temperature phase of the rare - earth - free MnBi Magnetic material, Journal of Science and Technology 54 (1A) (2016) 50-57.