Skip to main content
SpringerLink
Log in

Preparation and properties of hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders

  • Original Article
  • Published:
Rare Metals Aims and scope Submit manuscript

Abstract

The hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders were prepared under different hot-pressing temperatures (600–750 °C, at intervals of 25 °C) by the self-made hot-pressing equipment. The microstructure and magnetic properties of hot-deformed magnets prepared at different temperatures were also investigated. When the temperature is above 650 °C, the density of magnet reaches 7.5 g·cm−3. The optimum magnetic properties of magnetic induction intensity of Br = 1.3 T, optimum energy product of (BH)max = 282.5 kJ·m−3, intrinsic coercivity of Hcj = 1130.0 kA·m−1 of hot-deformed magnets are obtained at hot-pressing temperature of 650 °C. X-ray diffractometer pattern shows that the (00L) texture has been obtained. For the microstructural characteristic, on the one hand, the good magnetic performance is attributed to the fine platelet-like grains with an average length of 410–440 nm at the hot-pressing temperature range from 625 to 675 °C. On the other hand, the unaligned coarse grains are observed in all the samples. And the areal fraction of those is gradually increasing with the rise of the hot-pressing temperature, which tends to deteriorate the magnetic properties. The composition map shows the accumulation of Nd/Pr-rich phase in the coarse grains’ region.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

Similar content being viewed by others

References

  1. Volkov VV, Zhu Y. Magnetic structure and microstructure of die-upset hard magnets RE13.75Fe80.25B6 (RE = Nd, Pr) A possible origin of high coercivity. J Appl Phys. 1999;85(6):3254.

    Article  CAS  Google Scholar 

  2. Ju J, Wang Z, Yan A. Near-surface microstructure improvement for die-upset Nd–Fe–B magnets with an enhanced maximum energy product. J Alloy Compd. 2017;710:66.

    Article  Google Scholar 

  3. Ma BM, Brown D, Chen ZM. Developments in the processing and properties of NdFeb-type permanent magnets. J Magn Magn Mater. 2002;248:432.

    Article  Google Scholar 

  4. Lei W, Yu Y, Yang W, Feng M, Li H. A general strategy for synthesizing high-coercivity L10-FePt nanoparticles. Nanoscale. 2017;9(35):12855.

    Article  CAS  Google Scholar 

  5. Lei W, Xu J, Yu Y, Yang W, Hou Y, Chen D. Halide ion-mediated synthesis of L10-FePt nanoparticles with tunable magnetic properties. Nano Lett. 2018;18(12):7839.

    Article  CAS  Google Scholar 

  6. Yang W, Yu Y, Wang L, Yang C, Li H. Controlled synthesis and assembly into anisotropic arrays of magnetic cobalt-substituted magnetite nanocubes. Nanoscale. 2015;7(7):2877.

    Article  CAS  Google Scholar 

  7. Yang W, Lei W, Yu Y, Zhu W, George TA, Li XZ, Sellmyer DJ, Sun S. From FePt–Fe3O4 to L10-FePt–Fe nanocomposite magnets with a gradient interface. J Mater Chem C. 2015;3(27):7075.

    Article  CAS  Google Scholar 

  8. Yu Y, Mukherjee P, Tian Y, Li XZ, Shield JE, Sellmyer DJ. Direct chemical synthesis of L10-FePtAu nanoparticles with high coercivity. Nanoscale. 2014;6(20):12050.

    Article  CAS  Google Scholar 

  9. Yasuda HY, Kumano M, Nagase T, Kato R, Shimizu H. Tensile deformation behavior of Nd–Fe–B alloys. Scr Mater. 2011;65(8):743.

    Article  CAS  Google Scholar 

  10. Li L, Graham CD. Mechanism of texture formation by hot deformation in rapidly quenched FeNdB. J Appl Phys. 1990;67(9):4756.

    Article  Google Scholar 

  11. Yi P, Lee D, Yan A. Effects of compositions on characteristics and microstructures for melt-spun ribbons and die-upset magnets of Nd12.8+xFe81.2−x−y−zCoyGazB6. J Magn Magn Mater. 2010;322:3019.

    Article  CAS  Google Scholar 

  12. Wang YL, Luo Y, Wang ZL, Wu GY, Xie JJ, Yan WL, Yu DB. Coercivity enhancement in Nd–Fe–B magnetic powders by Nd–Cu–Al grain boundary diffusion. J Magn Magn Mater. 2018;458:85.

    Article  CAS  Google Scholar 

  13. Tian H, Jin DZ, Li Y, Zhu MY, Jin HM. Microstructure and magnetic properties of anisotropic Nd–Fe–B magnets fabricated by single-stage hot deformation. J Rare Earths. 2006;24(1):318.

    Article  Google Scholar 

  14. Wang H, Chen R, Yin W, Zhu M, Tang X, Wang Z, Jin C, Ju J, Lee D, Yan A. The effect of Nd–Cu diffusion during hot pressing and hot deformation on the coercivity and the deformation ability of Nd–Fe–B HDDR magnets. J Magn Magn Mater. 2017;438:35.

    Article  CAS  Google Scholar 

  15. Kirchner A, Liesert S. Preparation of anisotropic NdFeB magnets with different Nd contents by hot deformation (die-upsetting) using hot-pressed HDDR powders. J Alloy Compd. 1998;266:260.

    Article  Google Scholar 

  16. Lipiec W, Davies HA. The influence of the powder densification temperature on the microstructure and magnetic properties of anisotropic NdFeB magnets aligned by hot deformation. J Alloy Compd. 2010;491(1–2):694.

    Article  CAS  Google Scholar 

  17. Liu J, Sepehri-Amin H, Ohkubo T, Hioki K, Hattori A, Schrefl T, Hono K. Effect of Nd content on the microstructure and coercivity of hot-deformed Nd–Fe–B permanent magnets. Acta Mater. 2013;61(14):5387.

    Article  CAS  Google Scholar 

  18. Hou YH, Wang YL, Huang YL, Wang Y, Li S, Ma SC, Liu ZW, Zeng DC, Zhao LZ, Zhong ZC. Effects of Nd-rich phase on the improved properties and recoil loops for hot deformed Nd–Fe–B magnets. Acta Mater. 2016;115:385.

    Article  CAS  Google Scholar 

  19. Zhang T, Chen F, Zheng Y, Wen H, Wang J, Zhang L, Zhou L. Hot-deformed Nd–Fe–B magnets fabricated by dynamic loading with a high maximum energy product. Intermetallics. 2016;73:67.

    Article  CAS  Google Scholar 

  20. Wang XC, Zhu MG, Li W, Li YF, Lai B, Du A. Microstructure and magnetic properties of anisotropic hot-deformed magnet of different magnetic particle sizes. Rare Met. 2015;34(4):255.

    Article  Google Scholar 

  21. Lee D, Hilton JS, Liu S, Zhang Y, Hadjipanayis GC, Chen CH. Hot-pressed and hot-deformed nanocomposite (Nd, Pr, DY)2Fe14B/alpha-Fe-based magnets. IEEE Trans Magn. 2003;39(5):2947.

    Article  CAS  Google Scholar 

  22. Tang X, Sepehri-Amin H, Ohkubo T, Hioki K, Hattori A, Hono K. Coercivities of hot-deformed magnets processed from amorphous and nanocrystalline precursors. Acta Mater. 2017;123:1.

    Article  Google Scholar 

  23. Liu WQ, Chang C, Yue M, Yang JS, Zhang DT, Zhang JX, Liu YQ. Coercivity, microstructure, and thermal stability of sintered Nd–Fe–B magnets by grain boundary diffusion with TbH3 nanoparticles. Rare Met. 2017;36(9):718.

    Article  Google Scholar 

  24. Wang JM, Guo ZH, Jing Z, Du X, Yu NJ, Li MY, Zhu MG, Li M. Coercivity enhancement of hot-deformed Nd–Fe–B magnets with Pr–Cu alloy addition. Rare Met. 2018. https://doi.org/10.1007/s12598-017-0993-7.

    Article  Google Scholar 

  25. Liu J, Sepehri-Amin H, Ohkubo T, Hioki K, Hattori A, Schrefl T, Hono K. Grain size dependence of coercivity of hot-deformed Nd–Fe–B anisotropic magnets. Acta Mater. 2015;82:336.

    Article  CAS  Google Scholar 

  26. Lai B, Liu GJ, Wang HJ, Pan W, Zhu MG. Effect of hot-deformed temperature on magnetic properties of nanograin Nd–Fe–B magnets. Met Funct Mater. 2011;3:1.

    Google Scholar 

  27. Kwon H. Effect of grain size and die-upset temperature on texture in die-upset Nd–Fe–B magnet. IEEE Trans Magn. 2009;45:2590.

    Article  Google Scholar 

  28. Lin M, Wang HJ, Yi PP, Yan AR. Effects of excessive grain growth on the magnetic and mechanical properties of hot-deformed NdFeB magnets. J Magn Magn Mater. 2010;322(15):2268.

    Article  CAS  Google Scholar 

  29. Hu ZH, Li J, Chu LH, Liu Y. Effect of hot deformation temperature on the magnetic and mechanical properties of Nd–Fe–B magnets prepared by spark plasma sintering. J Magn Magn Mater. 2011;323(1):104.

    Article  CAS  Google Scholar 

  30. Li Z, Zhang M, Shen BG, Hu FX, Sun JR. Permanent magnetic properties of rapidly quenched (La, Ce)2Fe14B nanomaterials based on La–Ce mischmetal. J Alloy Compd. 2015;651:144.

    Article  Google Scholar 

  31. Skoug EJ, Meyer MS, Pinkerton FE, Tessema MM, Haddad D, Herbst JF. Crystal structure and magnetic properties of Ce2Fe14−xCoxB alloys. J Alloy Compd. 2013;574:552.

    Article  CAS  Google Scholar 

  32. Liu L, Sepehri-Amin H, Ohkubo T, Yano M, Kato A, Sakuma N, Shoji T, Hono K. Coercivity enhancement of hot-deformed Nd–Fe–B magnets by the eutectic grain boundary diffusion process using Nd62Dy20Al18 alloy. Scr Mater. 2017;129:44.

    Article  CAS  Google Scholar 

  33. Tang X, Chen R, Li M, Jin C, Yin W, Lee D, Yan A. Grain boundary diffusion behaviors in hot-deformed Nd2Fe14B magnets by PrNd-Cu low eutectic alloys. J Magn Magn Mater. 2018;445:66.

    Article  CAS  Google Scholar 

  34. Liu Y, Xu L, Wang Q, Li W, Zhang X. Development of crystal texture in Nd-lean amorphous Nd9Fe85B6 under hot deformation. Appl Phys Lett. 2009;94(17):172502.

    Article  Google Scholar 

  35. Lee YI, Huang GY, Shih CW, Chang WC, Chang HW, You JS. Coercivity enhancement in hot deformed Nd2Fe14B -type magnets by doping low-melting RCu alloys (R = Nd, Dy, Nd + Dy). J Magn Magn Mater. 2017;439:1.

    Article  CAS  Google Scholar 

  36. Li M, Chen R, Jin C, Yu J, Tang X, Chen G, Sun J, Wang Z, Yan A. Texture and microstructure improvement of hot-deformed magnets with platelet-like nano h-BN addition. Scr Mater. 2018;152:127.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was financially supported by the National Key Research and Development Program (No. 2016YFB0700902).

Author information

Authors and Affiliations

  1. National Engineering Research Center for Rare Earth Materials, General Research Institute for Nonferrous Metals, Beijing, 100088, China

    Peng Zhao, Yang Luo, Dun-Bo Yu, Hai-Jun Peng, Wen-Long Yan, Zi-Long Wang & Xin-Yuan Bai

  2. Grirem Advanced Materials Co., Ltd, Beijing, 100088, China

    Yang Luo, Dun-Bo Yu, Hai-Jun Peng, Wen-Long Yan, Zi-Long Wang & Xin-Yuan Bai

Authors
  1. Peng Zhao
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yang Luo
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Dun-Bo Yu
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Hai-Jun Peng
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Wen-Long Yan
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Zi-Long Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Xin-Yuan Bai
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Yang Luo.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zhao, P., Luo, Y., Yu, DB. et al. Preparation and properties of hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders. Rare Met. 40, 2033–2039 (2021). https://doi.org/10.1007/s12598-020-01473-7

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12598-020-01473-7

Keywords

Search

Navigation