Microstructure and Phase Evolution Mechanism in Hot-pressed and Hot-deformed Nd-Fe-B Magnets with Nd85Cu15 Addition
Source abstract
Abstract
Abstract Chemical composition and structure characteristics of the intergranular phases in Nd-Fe-B magnets play a key role in regulating the magnetic properties. However, it has still been a challenge to understand the evolution mechanism of grain boundary phases in hot-pressed and hot-deformed Nd-Fe-B magnets due to the complex phase composition and structure. In this work, grain boundary modification using Nd85Cu15 alloy has been applied to hot-pressed and hot-deformed Nd-Fe-B magnets. The structure evolution mechanism of the grain boundary phase during hot-pressing was studied by TEM analysis, which shows that an overall reaction, Nd + Nd26Ga7Co10 + Nd2Fe14B → Nd3Co + Nd5Fe2B6 + Nd6(Fe,Co)13Ga, occurs at 600°C in hot-pressed magnet with Nd85Cu15 addition. When the hot-deformation was conducted at 675°C abnormal grain growth was observed in hot-deformed magnets with or without Nd85Cu15 addition. In contrast, as the hot deformation temperature decreased to 630 °C, the uniform and ultra-fine Nd2Fe14B grains formed in the Nd85Cu15 doped magnet, which shows a significantly improved coercivity of 2.03 T and a squareness factor of 0.93.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Magnetic Properties of Alloys · Hydrogen Storage and Materials · Magnetic properties of thin films
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (55)
Show source-provided references
1. Hot-pressed neodymium-iron-boron magnets10.1063/1.95884 ↗
2. Strategy for high-coercivity Nd-Fe-B magnets10.1016/j.scriptamat.2012.06.038 ↗
3. Controlling the properties of high energy density permanent magnetic materials by different processing routes10.1088/0022-3727/33/17/201 ↗
4. Effect of Coarse Grains on Magnetic Properties of Nd-Fe-Co-B-Ga Die-Upset Magnets10.1109/20.104505 ↗
5. Effects of excessive grain growth on the magnetic and mechanical properties of hot-deformed NdFeB magnets10.1016/j.jmmm.2010.02.023 ↗
6. Evidence for reversal by nucleation in RE-Fe-B die-upset magnets10.1063/1.358291 ↗
7. Ferromagnetic grain boundary signature in die-upset Re-Fe-B magnets10.1016/0956-716X(95)00410-W ↗
8. Quasi-periodic layer structure of die-upset NdFeB magnets10.1016/S1002-0721(12)60342-1 ↗
9. Coercivity enhancement by inhibiting the formation of coarse grains region in hot-deformed Nd-Fe-B magnets with WC nano-particles addition10.1016/j.scriptamat.2017.01.024 ↗
10. The development of the microstructure of die-upset Nd-Fe-B magnets10.1016/0304-8853(90)90168-P ↗
11. Correlation between microstructural heterogeneity and energy product in hot deformed Nd-Fe-B magnets10.1016/j.jmmm.2020.166847 ↗
12. Effect of hot deformation temperature on the magnetic and mechanical properties of Nd–Fe–B magnets prepared by spark plasma sintering10.1016/j.jmmm.2010.08.040 ↗
13. Mechanism of texture formation by hot deformation in rapidly quenched FeNdB10.1063/1.344776 ↗
14. Diffusion of Nd-rich phase in the spark plasma sintered and hot deformed nanocrystalline NdFeB magnets10.1063/1.3682471 ↗
15. The microstructure of hot formed neodymium–iron–boron magnets with energy product 48 MGOe10.1063/1.352583 ↗
16. Improved hot workability and magnetic properties NdFeCoGaB hot deformed magnets10.1109/20.908772 ↗
17. High performance anisotropic NdFeB magnets prepared by dual-alloy die-upsetting10.1063/1.3679866 ↗
18. Improvement of magnetic performance of hot-deformed Nd-Fe-B magnets by secondary deformation process after Nd-Cu eutectic diffusion10.1016/j.actamat.2016.08.001 ↗
19. Coercivity enhancement of hydrogenation-disproportionation-desorption-recombination processed Nd-Fe-B powders by the diffusion of Nd-Cu eutectic alloys10.1016/j.scriptamat.2010.08.021 ↗
20. Development of a Dy-free NdFeB anisotropic bonded magnet with a high thermal stability
21. High-coercivity ultrafine-grained anisotropic Nd-Fe-B magnets processed by hot deformation and the Nd-Cu grain boundary diffusion process10.1016/j.actamat.2013.07.049 ↗
22. Low temperature diffusion process using rare earth-Cu eutectic alloys for hot-deformed Nd-Fe-B bulk magnets10.1063/1.4869062 ↗
23. High-coercivity hot-deformed Nd-Fe-B permanent magnets processed by Nd-Cu eutectic diffusion under expansion constraint10.1016/j.scriptamat.2014.03.002 ↗
24. Atomic-scale features of phase boundaries in hot deformed Nd-Fe-Co-B-Ga magnets infiltrated with a Nd-Cu eutectic liquid10.1016/j.actamat.2014.05.045 ↗
25. Microstructure and temperature dependent of coercivity of hot-deformed Nd-Fe-B magnets diffusion processed with Pr-Cu alloy10.1016/j.actamat.2015.08.013 ↗
26. Coercivity Enhancement of Hot-deformed Nd-Fe-B Magnets by the Eutectic Grain Boundary Diffusion Process10.1016/j.jallcom.2015.12.227 ↗
27. Enhancement of coercivity of hot-deformed Nd-Fe-B anisotropic magnet by low-temperature grain boundary diffusion of Nd60Dy20Cu20 eutectic alloy10.1016/j.scriptamat.2013.07.011 ↗
28. Coercivity enhancement of hot-deformed Nd-Fe-B magnets by the eutectic grain boundary diffusion process using Nd62Dy20Al18 alloy10.1016/j.scriptamat.2016.10.020 ↗
29. Coercivity enhancement in hot deformed Nd2Fe14B-type magnets by doping low-melting RCu alloys (R = Nd, Dy, Nd + Dy)10.1016/j.jmmm.2017.05.009 ↗
30. Comparison on the coercivity enhancement of hot deformed Nd2Fe14B-type magnets by doping R70Cu30 (R=Nd, Dy and Tb) alloy powders10.1109/TMAG.2017.2703128 ↗
31. Significant coercivity enhancement of hot deformed NdFeB magnets by doping Ce-containing (PrNdCe)70Cu30 alloys powders10.1016/j.scriptamat.2017.11.052 ↗
32. Overview of the Ways for Enhancing the Coercivity of Hot-Deformed Nd2Fe14B-Type Magnets
33. Improvement of Thermal Stability in Hot-Deformed Nd-Fe-B Magnets by Grain Refinement10.1016/j.scriptamat.2019.11.018 ↗
34. Magnetic Properties Improvement of Die-upset Nd-Fe-B Magnets by Dy-Cu Press Injection and Subsequent Heat Treatment10.1038/srep38335 ↗
35. Microstructure and Magnetic Properties of High Coercivity Die-Upset Nd-Fe-B Magnets by Nd-Cu Alloy Addition10.1109/TMAG.2015.2458984 ↗
36. Coercivity enhancement of Nd-Fe-B hot-deformed magnets by the eutectic grain boundary diffusion process using Nd-Ga-Cu and Nd-Fe-Ga-Cu alloys
37. Demagnetizing Factors for Rectangular Ferromagnetic Prisms10.1063/1.367113 ↗
38. Crystal structure of the compounds R26GaxCo17-x(R= La, Ce, Pr, Nd, Sm) and R26GaxNi17-x (R= Ce, Pr, Nd, Sm)
39. Note on the structure and composition of the B-rich ternary phase in the Nd-Fe-B system
40. Origins of inhomogeneous microstructure of hot-deformed nanocrystalline cylindrical Nd-Fe-B magnets and its effects on magnetization behaviors10.1016/j.jallcom.2019.04.076 ↗
41. Magnetic properties improvement of hot-deformed Nd-Fe-B permanent magnets by Pr-Cu eutectic pre-diffusion process10.1016/j.actamat.2019.05.065 ↗
42. Grain-size dependent demagnetizing factors in permanent magnets10.1063/1.4904854 ↗
43. Micromagnetism and microstructure of hard magnetic materials10.1088/0022-3727/29/9/008 ↗
44. Nd‐Fe‐B die‐upset and anisotropic bonded magnets (invited)10.1063/1.342394 ↗
45. Magnetic properties and thermal stabilities of Ga substituted Nd-Fe-Co-B magnets10.1109/TMAG.1987.1065291 ↗
46. Effects of Nd-rich phase on the improved properties and recoil loops for hot deformed Nd-Fe-B magnets10.1016/j.actamat.2016.06.015 ↗
47. High-resolution electron microscope study of the grain boundary phase in rapidly quenched Nd-Fe-B permanent magnet alloys10.1007/BF02648618 ↗
48. Crystallographic and magnetic alignment in die-upset Nd-Fe-B magnets10.1007/BF02833758 ↗
49. Investigation of domain wall pinning effect induced by annealing stress in sintered Nd-Fe-B magnet10.1016/j.jallcom.2015.04.017 ↗
50. A microstructure based magnetization reversal model in sintered Fe‐Nd‐B magnets. I10.1063/1.346945 ↗
51. Magnetization reversal process of anisotropic hot-deformed magnets observed by magneto-optical Kerr effect microscopy10.1016/j.jallcom.2018.08.231 ↗
52. The magnetization behavior and open recoil loops of hot-deformed Nd-Fe-B magnets infiltrated by low melting point PrNd-Cu alloys10.1063/1.4936154 ↗
53. Effects of long term annealing at 1000°C for 24 h on the microstructure and magnetic properties of Pr-Fe-B/Nd-Fe-B magnets based on Nd16Fe76B8 and Pr16Fe76B810.1016/S0925-8388(99)00506-X ↗
54. Microstructure and squareness factor: A quantitative correlation in (Nd, Pr)FeB sintered magnets10.1063/1.2821756 ↗
55. On the Squareness Factor Behavior of RE-FeB (RE Nd or Pr) Magnets Above Room Temperature10.1109/TMAG.2009.2025190 ↗