Synthesis and magnetic properties of bulk α″-Fe16N2/SrAl2Fe10O19 composite magnets

Dirba, Imants; Mohammadi, Mohammad; Rhein, F.; Gong, Qihua; Xu, Boyang; Krispin, M.; Gutfleisch, Oliver

doi:10.1016/j.jmmm.2020.167414

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…Additional important factor in favor of γ ′ -Fe 4 N is the chemical stability. The α ′′ -Fe 16 N 2 phase appears to be metastable and unless passivated on the surface or coated with a protective layer, it is prone to oxidation [23,63].…”

Section: Materials Optimization Approachmentioning

confidence: 99%

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Dirba

Chandra

Ablets

et al. 2022

J. Phys. D: Appl. Phys.

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In this work, we investigate alternative materials systems that, based on their intrinsic magnetic properties, have the potential to deliver enhanced heating power in magnetic fluid hyperthermia. The focus lies on systems with high magnetization phases, namely iron-nitrogen (Fe-N), iron-boron (Fe-B) and iron-carbon (Fe-C) compounds, and their performance in comparison to the conventionally used iron oxides, γ-Fe2O3, Fe3O4 and non-stoichiometric mixtures thereof. The heating power as a function of the applied alternating magnetic field frequency is calculated and the peak particle size with the maximum specific loss power (SLP) for each material is identified. It is found that lower anisotropy results in larger optimum particle size and more tolerance for polydispersity. The effect of nanoparticle saturation magnetization and anisotropy is simulated, and the results show that in order to maximize SLP, a material with high magnetization but low anisotropy provides the best combination. These findings are juxtaposed with experimental results of a comparative study of iron nitrides, namely α″-Fe16N2 and ε-Fe3N nanoparticles, and model nanoparticles of iron oxides. The former ones are studied as heating agents for magnetic fluid hyperthermia for the first time.

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Section: Materials Optimization Approachmentioning

confidence: 99%

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Dirba

Chandra

Ablets

et al. 2022

J. Phys. D: Appl. Phys.

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“…In case of nanocomposites, the hard phase attains polarization after soft phase under the reversal field, leads to the attainment of exchange spring magnetization by acting as a single-phase magnet [18]. The decrease in coercivity can be controlled by decreasing the ratio of the diameter of soft ferrites to domain wall width of the hard phase [19]. The doping of Al increases the magnetocrystalline anisotropy of hard phase, leading to an increase in the material's coercivity [20].…”

Section: Introductionmentioning

confidence: 99%

Tuning the magnetic properties of hard–soft Ba_0.5Sr_0.5Fe₁₀Al₂O₁₉ and Ni_0.1Co_0.9Fe₂O₄ nanocomposites via one pot sol–gel auto combustion method for permanent magnet applications

Abarna,

Ezhil Vizhi

2024

Nanotechnology

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Permanent magnets generate magnetic fields that can be sustained when a reverse field is supplied. These permanent magnets are effective in a wide range of applications. However, strategic rare-earth element demand has increased interest in replacing them with huge energy product (BH)max. Exchange-coupled hard/soft ferrite nanocomposites have the potential to replace a portion of extravagant rare earth element-based magnets. In the present, we have reported the facile auto-combustion synthesis of exchange coupled Ba0.5Sr0.5Fe10Al2O19 and Ni0.1Co0.9Fe2O4 nanocomposites by increasing the content of soft ferrite over the hard from x= 0.1 to 0.4 wt.%. The XRD combined with Rietveld analysis reflected the presence of hexaferrite and spinel ferrite without the existence of secondary phases. The absorption bands from the FTIR analysis proved that the presence of M-O bonds in tetrahedral site and octahedral sites. Rod and Non-spherical images from TEM represent the hexaferrite and spinel ferrite. Smooth M-H curve and single peak of SFD curve proves that the material has undergone a good exchange coupling. The nano powders displayed an increase in saturation magnetization and decrease in coercivity with the increases in the spinel content. The prepared nano composites were showing higher energy product. And the composite with the ratio x=0.2 displayed a higher value of (BH)max of 13.16 kJ/m3.

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“…For example, bulk composite magnets by using Al-doped Sr-hexaferrite SrAl 2 Fe 10 O 19 25 as the hard phase and environmentally friendly iron nitride α″-Fe 16 N 2 nanoparticles 26 obtained by hydrogen reduction of Fe 2 O 3 27 as the soft (semihard) phase were studied demonstrating that indeed adding α″-Fe 16 N 2 leads to increased M s and a slight increase in M r . 28 Another alternative in the search of new RE-free permanent magnet is the aforementioned Mn−Al-based alloy. 29 Although neither Mn nor Al is ferromagnetic, the metastable τ-MnAl phase found in the 47%−60% atomic composition interval exhibit ferromagnetism.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Recent works have shown that nanocomposite magnets offer a possibility to engineer magnetic properties by using a mixture of hard and soft phases. , Therefore, in addition to improved densification, enhancing the maximum energy product (BH) max of ferrite magnets by increasing the saturation magnetization M s via the exchange-spring-magnet principle has been tried and, if successful, would have great technological and economical importance. For example, bulk composite magnets by using Al-doped Sr-hexaferrite SrAl 2 Fe 10 O 19 as the hard phase and environmentally friendly iron nitride α″-Fe 16 N 2 nanoparticles obtained by hydrogen reduction of Fe 2 O 3 as the soft (semihard) phase were studied demonstrating that indeed adding α″-Fe 16 N 2 leads to increased M s and a slight increase in M r …”

Section: Introductionmentioning

confidence: 99%

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

Amato,

Becci,

Bollero

et al. 2023

ACS Sustainable Chem. Eng.

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Permanent magnets are fundamental constituents in key sectors such as energy and transport, but also robotics, automatization, medicine, etc. High-performance magnets are based on rare earth elements (RE), included in the European list of critical raw materials list. The volatility of their market increased the research over the past decade to develop RE-free magnets to fill the large performance/cost gap existing between ferrites and RE-based magnets. The improvement of hard ferrites and Mn–Al–C permanent magnets plays into this important technological role in the near future. The possible substitution advantage was widely discussed in the literature considering both magnetic properties and economic aspects. To evaluate further sustainability aspects, the present paper gives a life cycle assessment quantifying the environmental gain resulting from the production of RE-free magnets based on traditional hexaferrite and Mn–Al–C. The analysis quantified an advantage of both magnets that overcomes the 95% in all the considered impact categories (such as climate change, ozone depletion, human toxicity) compared to RE-based technologies. The benefit also includes the health and safety of working time aspects, proving possible reduction of worker risks by 3–12 times. The results represent the fundamentals for the development of green magnets that are able to significantly contribute to an effective sustainable transition.

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Synthesis and magnetic properties of bulk α″-Fe16N2/SrAl2Fe10O19 composite magnets

Cited by 7 publications

References 24 publications

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Tuning the magnetic properties of hard–soft Ba_0.5Sr_0.5Fe₁₀Al₂O₁₉ and Ni_0.1Co_0.9Fe₂O₄ nanocomposites via one pot sol–gel auto combustion method for permanent magnet applications

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

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Synthesis and magnetic properties of bulk α″-Fe16N2/SrAl2Fe10O19 composite magnets

Cited by 7 publications

References 24 publications

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe16N2 and ϵ-Fe3N nanoparticles

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe16N2 and ϵ-Fe3N nanoparticles

Tuning the magnetic properties of hard–soft Ba0.5Sr0.5Fe10Al2O19 and Ni0.1Co0.9Fe2O4 nanocomposites via one pot sol–gel auto combustion method for permanent magnet applications

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn–Al–C

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Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe₁₆N₂ and ϵ-Fe₃N nanoparticles

Tuning the magnetic properties of hard–soft Ba_0.5Sr_0.5Fe₁₀Al₂O₁₉ and Ni_0.1Co_0.9Fe₂O₄ nanocomposites via one pot sol–gel auto combustion method for permanent magnet applications