Microstructure and magnetic properties of alnico permanent magnetic alloys with Zr-B additives

Rehman, Sajjad Ur; Jiang, Qingzheng; Ge, Qing; Lei, Weikai; Zhang, Lili; Zeng, Qingwen; Haq, Anwar Ul; Liu, Renhui; Zhong, Zhenchen

doi:10.1016/j.jmmm.2017.11.043

Cited by 21 publications

(4 citation statements)

References 21 publications

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“…Additionally, the alloys have the best magnetic characteristics when they are composed of an aligned, extended, single-domain nanocrystalline precipitate of the highly magnetic α 1 phase regularly scattered in a weakly magnetic 2 matrix [ 8 ]. When a high-temperature composition of the alloy with a homogenous single-phase structure is brought inside the spinodal range at a lower temperature, it transforms into a separated two-phase structure, a process known as “spinodal decomposition.” The dissolved and decomposed alloy has a periodic microstructure in the order of hundreds of angstroms and is formed of two isomorphous phases, one of which is in the form of a small precipitate evenly dispersed in another phase that forms the matrix [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Single α-Phase for Promoting Ferromagnetic Properties of 44Fe–28Cr–22Co–3Mo–1Ti–2V Permanent Magnet with Varying Co Concentration for Energy Storage

et al. 2022

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The thermal stability and structural, microstructural and magnetic properties of (40 + x) Fe–28Cr–(26 − x) Co–3Mo–1Ti–2V magnets with x = 0, 2, 4 addition in cobalt content were investigated and presented. The magnetic alloys were synthesized by vacuum arc melting and casting technique in a controlled argon atmosphere. Magnetic properties in the alloys were convinced by single-step isothermal field treatment and subsequent aging. The alloys were investigated for thermal stability, structural, microstructural and magnetic properties via differential thermal analysis (DTA), X-ray diffractometery (XRD), optical microscopy (OM), field emission scanning electron microscope (FESEM) and DC magnetometer. Metallurgical grains of size 300 ± 10 μm were produced in the specimens by casting and refined by subsequent thermal treatments. The magnetic properties of the alloys were achieved by refining the microstructure, the optimization of conventional thermomagnetic treatment to modified single-step isothermal field treatment and subsequent aging. The best magnetic properties achieved for the alloy 44Fe–28Cr–22Co–3Mo–0.9Ti–2V was coercivity Hc = 890 Oe (71 kA/m), Br = 8.43 kG (843 mT) and maximum energy product (BH)max = 3 MGOe (24 kJ/m3). The enhancement of remanence and coercivity enabled by the isothermal field treatment was due to the elongation of the ferromagnetic phase and step aging treatment due to the increase in the volume fraction. This work is interesting for spin-based electronics to be used for energy storage devices.

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Section: Introductionmentioning

confidence: 99%

Optimization of Single α-Phase for Promoting Ferromagnetic Properties of 44Fe–28Cr–22Co–3Mo–1Ti–2V Permanent Magnet with Varying Co Concentration for Energy Storage

et al. 2022

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“…How to optimize the microstructure is crucial to obtain outstanding‐performance magnet. In the experiments, modifying the alloy composition, [ 12–14 ] applying magnetic field, [ 15–20 ] or controlling the cooling rate [ 21–23 ] are the most common methods to enhance magnetic properties. Usually, experimental research is a typical repetitive method, which consumes numerous human and material resources.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Magnetic Properties of Copper Mold Cast Nd–Fe–B Magnets Investigated by Phase‐Field and Micromagnetic Simulations

Wang

Qiu

et al. 2022

Adv Eng Mater

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The effects of several factors, including alloy composition, cooling rate, and external magnetic field, on the microstructures and magnetic properties of Nd–Fe–B ternary alloy are explored in detail by using phase‐field and micromagnetic simulations during the copper mold casting process. It is found that the characteristic of regional distribution is formed due to the temperature gradient in the alloy, and that Nd19Fe71.5B9.5 (at%) exhibits the highest coercivity and pretty good comprehensive magnetic properties among all alloys studied, which can be interpreted by the refinement of Nd2Fe14B grain size and thickness of Nd‐rich grain boundary phase. The cooling rate has significant influence on the average grain size and the amount of amorphous phase. An increase of cooling rate results in a decrease of grain size and an increase of amorphous phase, which then affect the coercivity and remanence of the magnet. Applying an external magnetic field is demonstrated to be a good approach to enhance the coercivity and remanence by refining the grain size and restraining the formation of amorphous phase and T2 phase.

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“…Also, the use of additives as sintering aids is an effective method to reduce sintering temperature. Although some additives deteriorate the magnetic properties of the ferrites, the choice of suitable sintering aid is a very actual problem to achieve synthetically low sintering temperature and high permeability [5,6]. It is shown that the single sintering aid declines the sintering temperature of ferrites due to the liquid phase formation [7].…”

Section: Introductionmentioning

confidence: 99%

Influence of MoO3 additive on grain growth and magnetic properties of Mg0.3Cu0.2Zn0.5Fe2O4 ceramics sintered at low temperature

Bahiraei

Ong

2021

J Mater Sci: Mater Electron

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In this research paper, microstructural, electromagnetic properties, and thermal stability, of (Mg 0.3 Cu 0.2 Zn 0.5 O) (Fe 2 O 3 ) ceramics were adjusted by using lowmelting point molybdenum trioxide (MoO 3 ) as additive. The required ferrite powders were synthesized through a cost-effective sol-gel method. The ferrite ceramics with high density and high permeability were prepared, using various content of MoO 3 (from 0.00 to 1.00 wt%) at low sintering temperature. Results indicate that MoO 3 not only improves density and grain growth of ferrite samples, but also effectively tailors the saturation magnetization (M s ), coercive field strength (H c ), initial permeability (l i ), and Curie temperature (T C ). For a qualitative comparison, the SEM images of both surface and fracture surface of the specimens were obtained. The results indicate that 0.25 wt% MoO 3 can promote grain growth, densification and uniformity, and reduce pores between grains of the sintered sample. In particular, MgCuZn ferrite with high bulk density (q = 4.7 g/cm 3 ), high initial permeability (l 0 = 460), high saturation magnetization (M s = 50.6 emu/g), and low coercivity (H c = 1.4 Oe) are obtained when the content of additive is 0.25 wt%. However, the excessive amount of MoO 3 deteriorates the grain size uniformity and weakens the magnetic properties due to the production of non-magnetic MoO 3 liquid phase.

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Microstructure and magnetic properties of alnico permanent magnetic alloys with Zr-B additives

Cited by 21 publications

References 21 publications

Optimization of Single α-Phase for Promoting Ferromagnetic Properties of 44Fe–28Cr–22Co–3Mo–1Ti–2V Permanent Magnet with Varying Co Concentration for Energy Storage

Optimization of Single α-Phase for Promoting Ferromagnetic Properties of 44Fe–28Cr–22Co–3Mo–1Ti–2V Permanent Magnet with Varying Co Concentration for Energy Storage

Microstructure and Magnetic Properties of Copper Mold Cast Nd–Fe–B Magnets Investigated by Phase‐Field and Micromagnetic Simulations

Influence of MoO3 additive on grain growth and magnetic properties of Mg0.3Cu0.2Zn0.5Fe2O4 ceramics sintered at low temperature

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