Optimization of magnetic properties of sintered (SmGdDy)(Co, Fe, Cu, Zr)z magnets by Dy–Co addition

et al. 2023

Chinese Phys. B

Four Sm2Co17 magnets with spin-reorientation-transition (SRT) of cell boundary phases (CBPs) are prepared by liquid-phase sintering. The temperature of the spin-reorientation-transition cell boundary phase (T SR 1:5) is regulated from 125 K to 195 K by adding 0 wt.%, 3 wt.%, 6 wt.%, and 9 wt.% Dy88Cu12 alloy powder. The effect of SRT in Sm2Co17 magnet CBPs on the temperature dependence of the magnetization (M-T) and coercivity (H-T) is systematically investigated. The temperature dependence of the magnetization is influenced by SRT in CBPs. The M-T curves measured during the heating process are larger than those measured during the cooling process when T < T SR 1:5. When T = T SR 1:5, there is a bifurcation point. When T > T SR 1:5, the M-T curves overlaps, and the M-T derivation curve shows that the magnetization of the magnet has a low temperature dependence of the magnetization after the T SR 1:5. With increasing T SR 1:5, the initial temperature of the low temperature dependence of magnetization shifts towards a higher temperature. The coercivity temperature coefficient becomes positive as the SRT effect increases, and the temperature range of the positive coercivity temperature coefficient moves towards higher temperatures as the T SR 1:5 increases. This reveals that SRT in CBPs has little effect on the temperature dependence of magnetization above T SR 1:5, while the temperature dependence of coercivity is optimized. The temperature range of magnetization and coercivity with low temperature dependence tends towards higher temperatures, which is conducive to the preparation of magnets with a low temperature coefficient at higher temperatures.

Section: Resultsmentioning

confidence: 99%

Effect of spin-reorientation transition of cell boundary phases on the temperature dependence of magnetization and coercivity in Sm₂Co₁₇ magnets

Liu

et al. 2023

Chinese Phys. B

“…12. The cell size, thickness of CBP, Cu content of CBP and intrinsic coercivity, H cj , in the samples are summarized in Table I.…”

Section: Resultsmentioning

confidence: 99%

“…In our previous study, we have found that Dy-Co liquid phase addition can regulate the microstructure of magnet and adjust its coercivity at the same time. 12 In this paper, the magnetic behavior during magnetization and reversal magnetization process of (Sm, Gd, Dy) (Co, Fe, Cu, Zr) z magnets with adding 0 wt%, 3 wt% and 5 wt% ratios of DyCo 0.51 liquid phase, which possess different cellular structures, are deeply discussed. 7.94 (MP) alloys were prepared by induction melting under argon atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Magnetization reversal process in (Sm, Dy, Gd) (Co, Fe, Cu, Zr)z magnets with different cellular structures

Liu

et al. 2017

AIP Advances

Self Cite

The high squareness Sm-Co magnet having H cb =10.6 kOe at 150°C AIP Advances 7, 056223 (2017) Magnetization reversal mechanism is found to vary with cellular structures by a comparative study of the magnetization processes of three (Sm, Dy, Gd) (Co, Fe, Cu, Zr) z magnets with different cellular structures. Analysis of domain walls, initial magnetization curves and recoil loops indicates that the morphology of cellular structure has a significant effect on the magnetization process, besides the obvious connection to the difference of domain energy density between cell boundary phase (CBP) and main phase. The magnetization of Sample 2 (with a moderate cell size and uniformly continuous CBPs) behaves as a strong coherence domain-wall pinning effect to the domain wall and lead to a highest coercivity in the magnet. The magnetization of Sample 1 (with thin and discontinuous CBPs) shows an inconsistent pinning effect to the domain wall while that of Sample 3 (with thick and aggregate CBPs) exhibits a two-phase separation magnetization. Both the two cases lead to lower coercivities. A simplified model is given as well to describe the relationships among cellular structure and magnetization behavior. © 2017 Author (s)

“…This result is slightly different from the other (SmRE)(Co,Fe,Cu,Zr) Z permanent magnets that the cell boundaries are thickening with the increasing RE content. 11,12 Therefore, it is thought to account for the adding of HRE Lu content, a uniform continuous cellular structure with the smaller cell size and the homogeneous cell boundary phase will lead to the increase in the magnetocrystalline anisotropy energy fluctuations between cell phase and cell boundary phase, 11,13 which may lead to the high coercivity for these alloys.…”

Section: Resultsmentioning

confidence: 99%

The microstructure and magnetic properties of (SmLu)(Co, Fe, Cu, Zr)_Z magnets with varying Lu content

Pan

et al. 2016

Materials Technology

The 2:17-type SmCo permanent magnet with nominal compositions of Sm 1-x Lu x (Co bal Fe 0.125 Cu 0.08 Zr 0.06 ) 7.4 (x = 0, 0.05, 0.1, 0.15) were prepared by a traditional powder metallurgy method. The influence of HRE Lu content on the microstructure and magnetic properties of these magnets were investigated systematically. HRE Lu addition has proved to result in relevant improvements in the microstructure and magnetic properties, especially in the coercivity H cj . It is shown that a higher coercivity and maximum energy product of about 35.92 kOe and 28.52 MGOe were obtained in the sample with x = 0.15. Meanwhile, the lattice constants have been discussed by indexing the selected area electron diffraction and HRTEM images.