Grain boundary infiltration in HDDR processed Nd2Fe14B magnets
Source abstract
Abstract
We investigate the grain boundary infiltration process of various low melting eutectic alloys for the coercivity enhancement of hydrogenation disproportionation desorption recombination (HDDR) processed Nd-Fe-B powders. Nd-based as well as heavy rare earth (Tb) and light rare earth (La, Ce) containing alloys were systematically studied: Nd 70Cu 30, Nd 90Al 10, Nd 80Ga 15Cu 5, Nd 62Fe 14Ga 20Cu 4, Nd 60Tb 10Cu 30, La 71Cu 29 and Ce 72Cu 28 . Moreover, the Fe content in the quaternary Nd-Fe-Ga-Cu system was varied to investigate the effect of grain boundary phase magnetism on the resultant coercivity. The largest coercivity enhancement, from 0.42 T in the as-HDDR powder to 1.88 T after infiltration was observed in the case of ternary Nd 80Ga 15Cu 5 composition. Furthermore, it also shows the best temperature stability with the infiltrated sample still exhibiting a coercivity of 0.58 T at 200 °C. Infiltration of light rare earth (La, Ce) based alloy did not increase coercivities due to poor wetting at the grain boundaries. Adding Fe to the grain boundary alloys was shown to enhance magnetization up to a certain extent without significant loss in coercivity. These findings demonstrate the effectiveness of grain boundary infiltration in HDDR-processed magnets without using heavy rare earths. The infiltration with non-magnetic material strongly decreases the intergranular interaction, reflected in a different magnetic domain evolution during the magnetization reversal process.
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Research context
OpenAlex topics: Magnetic Properties of Alloys · Magnetic properties of thin films · Hydrogen Storage and Materials
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (47)
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1. Magnetic materials and devices for the 21st century: Stronger, lighter, and more energy efficient10.1002/adma.201002180 ↗
2. Magnetic properties of R2Fe14B single crystals10.1063/1.334681 ↗
3. Dependence of coercivity on the anisotropy field in the Nd 2Fe14B-type sintered magnets10.1063/1.338725 ↗
4. Magnetization and magnetic anisotropy of R 2 Fe 1 4 B measured on single crystals10.1063/1.336611 ↗
5. Diffusion processes in hot-deformed Nd-Fe-B magnets with DyF3 additions10.1016/j.jmmm.2014.01.055 ↗
6. Grain interface modification and magnetic properties of Nd-Fe-B sintered magnets10.1143/JJAP.47.7876 ↗
7. Production of thick high-performance sintered neodymium magnets by grain boundary diffusion treatment with dysprosium-nickel-aluminum alloy10.1016/j.jmmm.2010.09.021 ↗
8. Clarifying the effects of la and Ce in the grain boundary diffusion sources on sintered NdFeB magnets10.1088/2053-1591/ab3756 ↗
9. Grain boundary diffusion treatment of sintered NdFeB magnets by low cost La-Al-Cu alloys with various Al/Cu ratios10.1016/j.jmmm.2019.165498 ↗
10. Significant progress of grain boundary diffusion process for cost-effective rare earth permanent magnets: A review10.1016/j.matdes.2021.110004 ↗
11. Hydrogenation, disproportionation and desorption (HDD): an effective processing route for NdFeB-type magnets10.1016/0022-5088(90)90071-Q ↗
12. Disproportionation in Nd16Fe76B8-type hydrides10.1016/0022-5088(90)90353-L ↗
13. T. Takeshita, R. Nakayama, No Title, in: Proceeding 10th Work. Rare Earth Magnets Their Appl., Kyoto, 1989: p. 551.
14. Fundamental and practical aspects of the hydrogenation, disproportionate, desorption and recombination process10.1088/0022-3727/29/9/006 ↗
15. Memory of Texture during HDDR Processing of NdFeB10.1109/TMAG.2003.815749 ↗
16. NdFeB anisotropic magnet powders produced by the HDDR process10.1016/0925-8388(93)90364-S ↗
17. Microstructures and crystallographic orientation of crystalline grains in anisotropic Nd-Fe-Co-B-(Ga or Zr) magnet powders produced by the hydrogenation-decomposition-desorption-recombination process10.1063/1.357091 ↗
18. C. Mishima, N. Hamada, H. Mitarai, Y. Honkura, Magnetic properties of NdFeB anisotropic magnet powder produced by the d-HDDR method, in: Proc. 16th Int. Work. Rare-Earth Magnets Their Appl 2000 The Japan Institute of Metals Sendai 873.
19. Texture inducement during HDDR processing of NdFeB10.1109/TMAG.2002.803078 ↗
20. Gutfleisch · Anisotropy Mechanism HDDR Processed NdFeB · 2003 · 37
21. Enhancement of the anisotropy of Nd-Fe-B powders by varying the HDDR conditions10.3379/jmsjmag.23.300 ↗
22. Effect of the disproportionation and recombination stages of the HDDR process on the inducement of anisotropy in Nd-Fe-B magnets10.1016/S0925-8388(99)00376-X ↗
23. Current status and recent topics of rare-earth permanent magnets10.1088/0022-3727/44/6/064001 ↗
24. Selective sensitivity in Kerr microscopy10.1063/1.4991820 ↗
25. Phase equilibria in the Nd-Cu system10.1016/0022-5088(83)90230-8 ↗
26. N. Clavaguera, Y. Du, Thermodynamic Calculation of the Nd-AI System, n.d.
27. Phase Relations in the Fe-Nd-B System
28. Additional ferromagnetic phases in the Fe-Nd-B system and the effect of a 600°C annealing10.1016/0022-5088(89)90543-2 ↗
29. Grain boundary and interface chemistry of an Nd-Fe-B-based sintered magnet10.1016/j.actamat.2011.10.043 ↗
30. Direct observation of ferromagnetism in grain boundary phase of Nd-Fe-B sintered magnet using soft x-ray magnetic circular dichroism10.1063/1.4902329 ↗
31. Magnetism of ultrathin intergranular boundary regions in Nd-Fe-B permanent magnets10.1016/j.actamat.2014.03.013 ↗
32. Transmission electron microscopy study on Nd-rich phase and grain boundary structure of Nd–Fe–B sintered magnets10.1063/1.1851017 ↗
33. Heavy rare earth free, free rare earth and rare earth free magnets - Vision and reality
34. Prospect for HRE-free high coercivity Nd-Fe-B permanent magnets10.1016/j.scriptamat.2018.03.012 ↗
35. Magnetization reversal in nucleation controlled magnets. II. Effect of grain size and size distribution on intrinsic coercivity of Fe‐Nd‐B magnets10.1063/1.342055 ↗
36. Interaction domains in isotropic, fine-grained Sm/sub 2/Fe/sub 17/N/sub 3/ permanent magnets10.1109/20.538869 ↗
37. Interaction domains in die-upset NdFeB magnets in dependence on the degree of deformation10.1016/j.jmmm.2003.12.1102 ↗
38. Magnetization reversal in textured NdFeB–Fe composites observed by domain imaging10.1016/j.jmmm.2010.05.064 ↗
39. Hubert · 1998
40. Magnetization processes in two different types of anisotropic, fully dense NdFeB hydrogenation, disproportionation, desorption, and recombination magnets10.1063/1.372628 ↗
41. Temperature-dependent Dy diffusion processes in Nd–Fe–B permanent magnets10.1016/j.actamat.2014.09.039 ↗
42. Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions10.1063/1.4822026 ↗
43. Grain boundary diffusion in nanocrystalline Nd-Fe-B permanent magnets with low-melting eutectics10.1016/j.actamat.2016.05.048 ↗
44. Coey · 2010
45. SmFe12-based hard magnetic alloys prepared by reduction-diffusion process10.1016/j.jallcom.2020.157993 ↗
46. Effect of Ga addition on the microstructure and magnetic properties of hydrogenation–disproportionation–desorption–recombination processed Nd–Fe–B powder10.1016/j.actamat.2009.10.035 ↗
47. Coercivity enhancement of hot-deformed Nd-Fe-B magnets by the eutectic grain boundary diffusion process10.1016/j.jallcom.2015.12.227 ↗