Investigation of Magnetic Properties and Coercivity Mechanisms in PrCo5/Nd2Fe14B Nanocrystalline Magnets AITranslate
Abstract AITranslate
RE-Fe-B based magnets exhibit excellent magnetic properties （high magnetization and coercivity） at room temperature but poor magnetic properties at high temperatures；whereas RE-Co based magnets present high thermal stability but their magnetization and energy product values are low compared with RE-Fe-B based magnets. If RE-Co based magnets with higher temperature stabilities are mixed with RE-Fe-B magnets with excellent magnetic properties，a hybrid magnet with outstanding magnetic properties，high temperature stability could be obtained. Thus，the respective disadvantages of the two magnets would be improved. The hybrid magnets consisting of RE-Fe-B and RE-Co are desirable from a magnetic perspective. In this work we presented recent studies of nanoscale hybrid magnets containing PrCo5 and Nd2Fe14B hard magnetic phases produced via hot-pressed and hot-deformed method using spark plasma sintering （SPS） technology，from mixtures of ball-milled powders obtained from nanocrystalline melt-spun ribbons. The effects of height reduction on anisotropy，magnetic interactions，coercivity mechanisms，and microstructure of the magnets were investigated. XRD patterns indicated that the dominant phases in the hot-pressed magnets were PrCo5，Nd2Fe14B and α-Fe. The height reduction played a key role in inducing the crystallographic alignment in the magnets. For the hot deformed magnets，the intensity of the diffraction peaks （006） and （105）representing the c-axis texture of Nd2Fe14B phase were enhanced compared to the hot pressed magnet，but they were still not the strongest peaks；meanwhile the （002） diffraction peak representing PrCo5 phase had a lower intensity than the hot pressed magnet，indicating that the deformation of Nd2Fe14B and PrCo5 was not synchronized during the deformation process，which might affect the anisotropy of the magnet. In order to characterize the crystallographic alignment quantitatively，the remanence ratio between the easy and hard axis were calculated. By the height reduction of 70%，80% and 90%，the remanence ratios were 0.51，0.53 and 0.49，respectively，suggesting that the crystallographic alignment was already developed to some extent in the hot deformed magnets. The magnetic properties tested show that the remanence of the hot-deformed magnet increased first and then decreases with the increase height reduction，while the coercivity decreased with the increase height reduction. The openness of the recoil loops in hot-pressed and hot-deformed magnets was observed and it increased with the increase of height reduction. Quantitative characterization of the recoil loops indicated that the incomplete exchange coupling in the hot-deformed magnets became more evident with increasing height reduction，which led to the decline of intergranular exchange coupling. To investigate the exchange coupling between the grains，Henkel plot was measured for the hot-pressed and hot-deformed magnets. The Henkel plot of hot-pressed magnet showed a positive value and a larger negative value；differently the hot-deformed magnets only had negative values without positive part，the negative parts showed that there were dipolar interactions between PrCo5 and Nd2Fe14B and the interactions also increased with the increase of height reduction. Minor hysteresis loops were used to investigate the coercivity mechanism. The coercivity mechanisms of hot-pressed and hot-deformed magnets were pinning mechanism，the pinning effect gradually weakened with increasing height reduction. A region of elemental transition was observed in the hot-pressed magnet.
KeyWords AITranslate
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Basic Information:
DOI：10.13373/j.cnki.cjrm.XY24080011
Chinese Library Classification Number:O616
Citation Information:
RE-Fe-B based magnets exhibit excellent magnetic properties （high magnetization and coercivity） at room temperature but poor magnetic properties at high temperatures；whereas RE-Co based magnets present high thermal stability but their magnetization and energy product values are low compared with RE-Fe-B based magnets. If RE-Co based magnets with higher temperature stabilities are mixed with RE-Fe-B magnets with excellent magnetic properties，a hybrid magnet with outstanding magnetic properties，high temperature stability could be obtained. Thus，the respective disadvantages of the two magnets would be improved. The hybrid magnets consisting of RE-Fe-B and RE-Co are desirable from a magnetic perspective. In this work we presented recent studies of nanoscale hybrid magnets containing PrCo5 and Nd2Fe14B hard magnetic phases produced via hot-pressed and hot-deformed method using spark plasma sintering （SPS） technology，from mixtures of ball-milled powders obtained from nanocrystalline melt-spun ribbons. The effects of height reduction on anisotropy，magnetic interactions，coercivity mechanisms，and microstructure of the magnets were investigated. XRD patterns indicated that the dominant phases in the hot-pressed magnets were PrCo5，Nd2Fe14B and α-Fe. The height reduction played a key role in inducing the crystallographic alignment in the magnets. For the hot deformed magnets，the intensity of the diffraction peaks （006） and （105）representing the c-axis texture of Nd2Fe14B phase were enhanced compared to the hot pressed magnet，but they were still not the strongest peaks；meanwhile the （002） diffraction peak representing PrCo5 phase had a lower intensity than the hot pressed magnet，indicating that the deformation of Nd2Fe14B and PrCo5 was not synchronized during the deformation process，which might affect the anisotropy of the magnet. In order to characterize the crystallographic alignment quantitatively，the remanence ratio between the easy and hard axis were calculated. By the height reduction of 70%，80% and 90%，the remanence ratios were 0.51，0.53 and 0.49，respectively，suggesting that the crystallographic alignment was already developed to some extent in the hot deformed magnets. The magnetic properties tested show that the remanence of the hot-deformed magnet increased first and then decreases with the increase height reduction，while the coercivity decreased with the increase height reduction. The openness of the recoil loops in hot-pressed and hot-deformed magnets was observed and it increased with the increase of height reduction. Quantitative characterization of the recoil loops indicated that the incomplete exchange coupling in the hot-deformed magnets became more evident with increasing height reduction，which led to the decline of intergranular exchange coupling. To investigate the exchange coupling between the grains，Henkel plot was measured for the hot-pressed and hot-deformed magnets. The Henkel plot of hot-pressed magnet showed a positive value and a larger negative value；differently the hot-deformed magnets only had negative values without positive part，the negative parts showed that there were dipolar interactions between PrCo5 and Nd2Fe14B and the interactions also increased with the increase of height reduction. Minor hysteresis loops were used to investigate the coercivity mechanism. The coercivity mechanisms of hot-pressed and hot-deformed magnets were pinning mechanism，the pinning effect gradually weakened with increasing height reduction. A region of elemental transition was observed in the hot-pressed magnet.
quote
| GB/T 7714-2015 | [1] Jianhua Zuo, Wei Lu, Yu Bo, et al. Investigation of Magnetic Properties and Coercivity Mechanisms in PrCo5/Nd2Fe14B Nanocrystalline Magnets[J]. Chinese Journal of Rare Metals, 2025, 49(10): 1635-1643. DOI:10.13373/j.cnki.cjrm.XY24080011. |
| MLA | [1] Jianhua Zuo, et al., "Investigation of Magnetic Properties and Coercivity Mechanisms in PrCo5/Nd2Fe14B Nanocrystalline Magnets." Chinese Journal of Rare Metals, vol. 49, no. 10, 2025, pp. 1635-1643, https://doi.org/10.13373/j.cnki.cjrm.XY24080011. |
| APA | [1] Jianhua Zuo, Wei Lu, Yu Bo, Chenyu Li, Feng Pan, Xiangming Ju, Wenxia Huo, Ming Zhang, & Yongfeng Li. (2025). Investigation of Magnetic Properties and Coercivity Mechanisms in PrCo5/Nd2Fe14B Nanocrystalline Magnets. Chinese Journal of Rare Metals, 49(10), 1635-1643. https://doi.org/10.13373/j.cnki.cjrm.XY24080011 |
| IEEE | [1] Jianhua Zuo, Wei Lu, Yu Bo, Chenyu Li, Feng Pan, Xiangming Ju, Wenxia Huo, Ming Zhang, and Yongfeng Li, "Investigation of Magnetic Properties and Coercivity Mechanisms in PrCo5/Nd2Fe14B Nanocrystalline Magnets," Chinese Journal of Rare Metals, vol. 49, no. 10, pp. 1635-1643, 2025, doi: 10.13373/j.cnki.cjrm.XY24080011. keywords: {PrCo/NdFeB;hot press and hot deformation;anisotropy;interaction;coercivity mechanism} |