Improved Coercivity in Cu-Doped SmCo5 Nanocomposite Powders Obtained by Low Temperature Annealing

doi:10.1007/s40195-025-01827-z

Abstract

Abstract:

In this work, nanocrystalline SmCo₅-Cu nanocomposite powders were fabricated from the ball-milled amorphous matrix by crystallization annealing which is lower than the traditional sintering temperature ~ 1000 °C for bulk SmCo₅ bulk magnets. Annealed Cu-doped SmCo₅ powders have a higher coercivity compared to that of Cu-free SmCo₅ one due to the combined effects of refinement effect of grain size and the pinning effect induced by Cu doping. The peak of coercivity (H_c) is located at 600 °C for annealed Cu-doped SmCo₅, which is ascribed to the improved pinning field. The pinning effect became reduced when the annealing was done at even higher temperatures. More importantly, the best comprehensive magnetic properties, including a maximum magnetic energy product (BH)_max of 12.2 MGOe together with a coercivity of 31.8 kOe and a remanence of 64.3 emu/g, could be achieved for SmCo₅-3 wt% Cu by low temperature annealing. These results demonstrate that isotropic Cu-doped SmCo₅ nanocrystalline powders are promising precursors for the fabrication of high-performance bulk magnets.

Key words: Rare earth permanent magnet, SmCo₅, Nanocrystalline, Refinement, Pinning mechanism, Crystallization

Longfei Ma, Yingzhengsheng Huang, Wei Quan, Qiang Zheng, Juan Du. Improved Coercivity in Cu-Doped SmCo₅ Nanocomposite Powders Obtained by Low Temperature Annealing[J]. Acta Metallurgica Sinica (English Letters), 2025, 38(4): 587-596.

Figures/Tables 7

Fig. 1 Intrinsic coercivity Hci (T) a and the change of coercivity ΔHci (T) of different Cu doping compared with that of Cu-free SmCo5 b. The first derivative of the initial magnetization curves (dM/dH) for SmCo5-3 wt% Cu annealed at different temperatures c and SmCo5 containing different Cu contents annealed at 600 °C d. The initial magnetization curves of c, d are shown as insets

Table 1 Magnetic properties, including coercivity Hci, remanence Mr, maximum magnetic energy product (BH)max of different weight percent of Cu-doped SmCo5 annealed at different temperatures for 30 min

Cu doping (wt%)	Temperature (°C)	H_ci (kOe)	ΔH_ci (kOe)	M_r (emu/g)	(BH)_max (MGOe)
0	500	19.7		75.8	15.9
1	500	22.8	3.1	70.3	14.0
3	500	26.0	6.3	66.4	12.5
5	500	24.8	5.1	63.1	11.2
0	550	25.5	-	70.7	13.8
1	550	28.1	2.6	69.4	13.4
3	550	31.8	6.3	64.3	12.2
5	550	31.4	5.9	59.2	11.2
0	600	26.1	-	66.6	12.2
1	600	31.7	5.6	65.4	11.7
3	600	34.2	8.1	59.7	10.1
5	600	33.6	7.5	54.3	9.2
0	650	28.5	-	62.9	11.1
1	650	31.4	2.9	62.5	9.9
3	650	32.5	4	56.8	8.2
5	650	32.1	3.6	52.5	7.9

Fig. 2 XRD patterns of different Cu doped SmCo5 annealed at 600 °C for 30 min a, b the calculated grain size by Scherrer formula for SmCo5 containing different Cu contents annealed at different temperatures for 30 min

Fig. 3 Demagnetization curves of SmCo5 containing 0 and 1 wt% Cu annealed at 600 °C a, the demagnetization curves of SmCo5 containing 1 wt% Cu annealed at different temperatures b, the relationship between remanence c, maximum magnetic energy product (BH)max d and annealing temperatures for SmCo5 containing different Cu contents

Fig. 4 XRD patterns of SmCo5 containing 1 wt% Cu annealed at different temperatures for 30 min

Fig. 5 TEM image of the SmCo5-1 wt% Cu annealed at 600 °C for 30 min a, STEM image of the SmCo5-1 wt% Cu annealed at 600 °C for 30 min b and the corresponding elemental maps for Sm c, Co d, Cu e, respectively

Fig. 6 Line scanning of three elements, Sm, Co and Cu a, the ratio of (Co + Cu)/Sm along the scanning line b for SmCo5-3 wt% Cu annealed at 600 °C for 30 min. The image of the line scanning results is shown in a

References 35

[1]	K. Kumar, J. Appl. Phys. 63, R13 (1988)
[2]	K. Strnat, G. Hoffer, J. Olson, W. Ostertag, J.J. Becker, J. Appl. Phys. 38, 1001 (1967)
[3]	H. Kronmüller, K.D. Durst, M. Sagawa, J. Magn. Magn. Mater. 74, 291 (1988)
[4]	K.J. Strnat, in Ferromagnetic Materials. ed. by E.P. Wohlfarth, K.H.J. Buschow (North-Holland, Amsterdam, 1988), p. 131
[5]	J. Ding, P.G. McCormick, R. Street, J. Alloy. Compd. 228, 102 (1995)
[6]	A.R. Yan, W.Y. Zhang, H.W. Zhang, B.G. Shen, J. Magn. Magn. Mat. 210, 10 (2000)
[7]	A. Laslo, C.V. Colin, O. Isnard, M. Guillot, J. Appl. Phys. 107, 09A732 (2010)
[8]	A.A. Kündig, R. Gopalan, T. Ohkubo, K. Hono, Scr. Mater. 54, 2047 (2006)
[9]	T. Saito, D. Nishio-Hamane, J. Alloy. Compd. 585, 423 (2014)
[10]	T. Fukuzaki, H. Iwane, K. Abe, T. Doi, R. Tamura, T. Oikawa, J. Appl. Phys. 115, 17A760 (2014)
[11]	J.C. Téllez-Blanco, R. Grössinger, R. Sato Turtelli, J. Alloy. Compd. 281, 1 (1998)
[12]	J.C. Téllez-Blanco, R. Sato Turtelli, R. Grössinger, D. Givord, D. Eckert, A. Handstein, K.H. Müller, J. Magn. Magn. Mat. 238, 6 (2002)
[13]	W.Y. Zhang, X.D. Zhang, Y.C. Yang, B.G. Shen, J. Alloy. Compd. 353, 274 (2003)
[14]	R. Gopalan, K. Hono, A. Yan, O. Gutfleisch, Scr. Mater. 60, 764 (2009)
[15]	Y. Hong, Z.G. Qiu, Z.G. Zheng, G. Wang, H.Y. Yu, D.Y. Chen, G.B. Han, D.C. Zeng, J.P. Liu, Acta Mater. 164, 627 (2019) DOI
[16]	L. Weissitsch, M. Stückler, S. Wurster, J. Todt, P. Knoll, H. Krenn, R. Pippan, A. Bachmaier, Nanomaterials 12, 963 (2022)
[17]	J.K. Fan, Q. Zheng, R. Bao, J.H. Yi, J. Du, J. Mater. Sci. Technol. 37, 181 (2020)
[18]	J. Zhang, F. Wang, Y. Zhang, J. Song, Y. Zhang, B. Shen, J. Sun, J. Nanosci. Nanotechnol. 12, 1109 (2012)
[19]	J. Zhang, Y.K. Takahashi, R. Gopalan, K. Hono, J. Magn. Magn. Mater. 310, 1 (2007)
[20]	G.C. Hadjipanayis, J.M.D. Coey, Rare-Earth Iron Permanent Magnets, 2nd edn. (Clarendon Press, Oxford, 1996), p.286
[21]	H. Sepehri-Amin, J. Thielsch, J. Fischbacher, T. Ohkubo, T. Schrefl, O. Gutfleisch, K. Hono, Acta Mater. 126, 1 (2017)
[22]	H. Nagel, A. Menth, IEEE Trans. Magn. 14, 671 (1978)
[23]	W.M. Cheng, Y.F. Dai, H. Hu, X.M. Cheng, X.S. Miao, J. Electron. Mater. 41, 2178 (2012)
[24]	J. Ding, P.G. McCormick, R. Street, J. Alloy. Compd. 191, 197 (1993)
[25]	J. Ding, P.G. McCormick, R. Street, J. Magn. Mater. 123, L239(1993)
[26]	Y.K. Takahashi, T. Ohkubo, K. Hono, J. Appl. Phys. 100, 053913 (2006)
[27]	H.R. Lashgari, D. Chu, S. Xie, H. Sun, M. Ferry, S. Li, J. Non-Cryst. Solids 391, 61 (2014)
[28]	O. Akdogan, H. Sepehri-Amin, N.M. Dempsey, T. Ohkubo, K. Hono, O. Gutfleisch, T. Schrefl, D. Givord, Adv. Electron. Mater. 1, 1500009 (2015)
[29]	D.J. Craik, E.W. Hill, A.J. Harrison, IEEE Trans. Magn. 11, 1379 (1979)
[30]	S. Li, L. Ma, J. Fan, J. Yang, Q. Zheng, B. Bian, J. Zhang, J. Du, J. Mater. Sci. Technol. 88, 183 (2021)
[31]	L. Ma, W. Quan, J. Fan, Y. Chen, Q. Zheng, B. Bian, J. Zhang, J. Du, J. Mater. Sci. Technol. 144, 161 (2023)
[32]	R. Skomski, J. Phys. Condens. Matter 15, R841 (2003)
[33]	H. Nagel, J. Appl. Phys. 50, 1026 (1979)
[34]	H. Kronmiiller, K.D. Durst, W. Ervens, W. Femengel, IEEE Trans. Magn. 20, 1569 (1984)
[35]	G.C. Hadjipanayis, R.C. Harzelton, K.R. Lawless, L.S. Horton, IEEE Trans. Magn. 18, 1460 (1982)

Improved Coercivity in Cu-Doped SmCo₅ Nanocomposite Powders Obtained by Low Temperature Annealing

RichHTML

PDF (PC)

Knowledge

Abstract

Cite this article

share this article

Figures/Tables 7

References 35

Related Articles 15

Recommended Articles

Metrics

Comments

[1]	Peng Liu, Hongliang Liu, Jun Liu, Chaoyun Yang, Hang Liu, Chengwu Zheng, Yikun Luan, Mingguang Li, Dianzhong Li. Manipulating the texture configuration and formability of interstitial-free steels through low-oxygen rare earth addition [J]. Metals Advances, 2026, 40(2): 101-109.
[2]	Sen Ge, Ben Niu, Zhen-Hua Wang, Qian-Fu Pan, Chao-Hong Liu, Qing Wang. Recrystallization Behavior and Mechanical Property of a Medium-Si 12%Cr Reduced Activation Ferritic/Martensitic Steel Cladding Tube During the Manufacture [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(8): 1385-1396.
[3]	Qi Zhou, Yufeng Xia, Yu Duan, Baihao Zhang, Yuqiu Ye, Peitao Guo, Lu Li. Microstructure and Mechanical Properties of Yb-Containing AZ80 Cast Alloys [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(7): 1095-1108.
[4]	Meisa Zhou, Kun-Ming Pan, Xiao-Ye Zhou, Shulong Ye, Shaojie Du, Hong-Hui Wu. Surface Wear Behavior of Nanograined NbMoTaW Refractory High-Entropy Alloys via Nano-scratching Simulations [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(6): 946-960.
[5]	Hongyang Zhang, Huihui Nie, Zhijian Li, Hongsheng Chen, Wei Liang, Liuwei Zheng. Evolution of Microstructure and Mechanical Properties of AZ31 Sheets with Different Initial Microstructures During the Corrugated Wide Limit Alignment Process [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(6): 1012-1028.
[6]	Hao Zhang, Le Zai, Xiaohuai Xue. Enhancing the Mechanical Properties Induced by Ta Microalloying in TIG-Welded Ti₂AlNb-Based Intermetallic Alloy [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(3): 419-434.
[7]	Tianyi Zeng, Zirui Luo, Hao Chen, Wei Wang, Ke Yang. Flow Behavior and Dynamic Recrystallization Mechanism of CSS-42L Bearing Steel During Hot Compression Deformation [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(3): 465-480.
[8]	Nafiseh Mollaei, Seyed Mahmood Fatemi, Mohammad Reza Aboutalebi, Seyed Hossein Razavi, Wiktor Bednarczyk. Microstructure, Texture, Mechanical Properties, and Corrosion Behavior of Biodegradable Zn-0.2Mg Alloy Processed by Multi-Directional Forging [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(3): 507-525.
[9]	Xiangru Guo, Jian Zhang, Tieqiang Kong, Junjie Shen, Qingjian Liu, Chaoyang Sun, Peipei Li. Unraveling the Discontinuous Dynamic Recrystallization of the TC17 Titanium Alloy during Hot Deformation by Crystal Plasticity Modeling [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(12): 2243-2264.
[10]	Fang-Fang Cao, Cui-Ju Wang, Kai-Bo Nie, Quan-Xin Shi, Yi-Jia Li, Kun-Kun Deng. Mechanical Properties and Work Hardening Behavior of Ti_p/Mg-Gd-Y-Zn Composites [J]. Acta Metallurgica Sinica (English Letters), 2025, 38(10): 1777-1793.
[11]	Gang Zeng, Hong Liu, Jing-Peng Xiong, Jian-Long Li, Yong Liu. Enhanced Grain Refining Effect of Mg-Zr Master Alloy on Magnesium Alloys via a Synergistic Strategy Involving Heterogeneous Nucleation and Solute-Driven Growth Restriction [J]. Acta Metallurgica Sinica (English Letters), 2024, 37(8): 1354-1366.
[12]	Ping Li, Shuangwu Xia, Junfu Dong, Liangwei Dai, Zhicheng Luo, Kemin Xue. Effect of Bimodal Quasicrystal Phase on the Dynamic Recrystallization of Mg-Zn-Gd Alloy during High-Pressure Torsion [J]. Acta Metallurgica Sinica (English Letters), 2024, 37(7): 1128-1134.
[13]	Xiang Kong, Yu Wang, Hong Xu, Haotian Fan, Yuewu Zheng, Beibei Xie. NbB₂ Modified Al-Cu Alloys Fabricated by Freeze-Ablation Casting under High Cooling Rate Solidification [J]. Acta Metallurgica Sinica (English Letters), 2024, 37(5): 921-938.
[14]	Chuan Rong, Jieren Yang, Xiaoliang Zhao, Ke Huang, Ying Liu, Xiaohong Wang, Dongdong Zhu, Ruirun Chen. Microstructure Recrystallization and Mechanical Properties of a Cold-Rolled TiNbZrTaHf Refractory High-Entropy Alloy [J]. Acta Metallurgica Sinica (English Letters), 2024, 37(4): 633-647.
[15]	Hengrui Hu, Jiayu Qin, Yunpeng Zhu, Jinhui Wang, Xiaoqiang Li, Peipeng Jin. Hot Deformation Behavior and Microstructures Evolution of GNP-Reinforced Fine-Grained Mg Composites [J]. Acta Metallurgica Sinica (English Letters), 2024, 37(3): 407-424.