Morphology and magnetic properties of pressed barium hexaferrite BaFe12O19 materials

Винник, Д.А.; Chernukha, A.S.; Gudkova, S.A.; Живулин, В.Е.; Trofimov, Evgeny; Tarasova, A. Yu.; Жеребцов, Д. А.; Kalandija, M.; Trukhanov, S. V.; Senin, A.V.; Исаенко, Л. И.; Перов, Н.С.; Niewa, Rainer

doi:10.1016/j.jmmm.2017.11.085

Cited by 24 publications

(13 citation statements)

References 29 publications

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“…The optimal temperature of the solid-state synthesis of Ba hexaferrite, which ensures a stable formation and crystal growth, was earlier established experimentally to be 1623 K [31]. Figure 1 shows the crystals obtained at this temperature from mixtures of barium carbonate and iron(III) oxide to range within the μm-size.…”

Section: Discussionmentioning

confidence: 86%

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

et al. 2017

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Barium hexaferrite powder samples with grains in the μm-range were obtained from solid-state sintering, and crystals with sizes up to 5 mm grown from PbO, Na2CO3, and BaB2O4 fluxes, respectively. Carbonate and borate fluxes provide the largest and structurally best crystals at significantly lower growth temperatures of 1533 K compared to flux-free synthesis (1623 K). The maximum synthesis temperature can be further reduced by the application of PbO-containing fluxes (down to 1223 K upon use of 80 at % PbO), however, Pb-substituted crystals Ba1–xPbxFe12O19 with Pb contents in the range of 0.23(2) ≤ x ≤ 0.80(2) form, depending on growth temperature and flux PbO content. The degree of Pb-substitution has only a minor influence on unit cell and magnetic parameters, although the values for Curie temperature, saturation magnetization, as well as the coercivity of these samples are significantly reduced in comparison with those from samples obtained from the other fluxes. Due to the lowest level of impurities, the samples from carbonate flux show superior quality compared to materials obtained using other methods.

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Section: Discussionmentioning

confidence: 86%

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

et al. 2017

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“…However, the influence of nanoparticle consolidation is largely neglected in the literature, as it presents numerous difficulties such as excessive crystallite growth, impurity formation, dilution of magnetic material due to binding elements, application of high external magnetic fields during compaction, or lack of magnetic orientation in the produced magnet. While many studies have been performed on the synthesis of SrFe 12 O 19 nanocrystallites obtaining promising magnetic properties, ,− few studies − cover the subsequent step in the production of permanent hexaferrite magnets, i.e., the compaction of nanoparticles into a final dense bulk magnet.…”

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confidence: 99%

Nanoengineered High-Performance Hexaferrite Magnets by Morphology-Induced Alignment of Tailored Nanoplatelets

Saura-Múzquiz

Granados-Miralles

Andersen

et al. 2018

ACS Appl. Nano Mater.

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Magnetic materials are ubiquitous in electric devices and motors making them indispensable for modern-day society. The hexaferrites currently constitute the most widely used permanent magnets (PMs), accounting for 85% (by weight) of the global sales of PMs. This work presents a complete bottom-up nanostructuring protocol for preparation of magnetically aligned, high-performance hexaferrite PMs with a record-high (BH)max for dry-processed ferrites. The procedure includes the supercritical hydrothermal flow synthesis of anisotropic magnetic-single-domain strontium hexaferrite (SrFe12O19) nanocrystallites of various sizes, and their subsequent compaction into bulk magnets by spark plasma sintering (SPS). Interestingly, Rietveld modeling of neutron powder diffraction data reveals a significant difference between the magnetic structure of the thinnest nanoplatelets and the bulk compound, indicating the Sr-containing atomic layer to be the termination layer. Subsequently, high-density SrFe12O19 magnets (>95% of the theoretical density) are produced by SPS of the flow-synthesized nanoplatelets. Texture analysis by X-ray pole figure measurements demonstrates how the anisotropic shape of the nanoplatelets causes a self-induced alignment during SPS, without application of an external magnetic field. The self-induced texture is accompanied by crystallite growth along the magnetic easy-axis, i.e., the thickness of the platelets, resulting in high-performance PMs with square hysteresis curves and (BH)max of 30 kJ/m3. The (BH)max is further enhanced by annealing, reaching 36 kJ/m3 after 4 h at 850 °C, which exceeds the (BH)max of the highest grade of dry-processed commercial ferrites worldwide.

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“…In the aspect of preparing methods, many kinds of preparing methods have been used to synthesize high‐performance M‐type ferrite. Vinnik et al [2] . prepared single‐phase BaFe 12 O 19 materials by solid‐state reaction method, and compacted them into blocks under different pressures.…”

Section: Introductionmentioning

confidence: 99%

“…In the aspect of preparing methods, many kinds of preparing methods have been used to synthesize highperformance M-type ferrite. Vinnik et al [2] prepared single-phase BaFe 12 O 19 materials by solid-state reaction method, and compacted them into blocks under different pressures. It was found that the highest apparent density was obtained by compaction under 108 kN/cm 2 ; the lowest coercivity was detected by compaction under 121 kN/cm 2 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Magnetic and Electrical Characteristics of Ba‐Sr Hexaferrites Substituted with Samarium, Chromium and Aluminum

et al. 2021

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A series of M‐type Ba−Sr hexaferrites of composition Ba0.20Sr0.80‐xSmxFe12‐y(Cr0.5Al0.5)yO19 (x=0.00–0.40; y=0.00–0.32) were prepared by solid‐state reaction route. XRD patterns reveals that there is a single magnetoplumbite phase in the hexaferrites with the substitutiom of Sm (0.00≤x≤0.20) and CrAl (0.00≤y≤0.16) contents, while for the hexaferrites containing Sm (x≥0.30) and CrAl (y≥0.24), impurity phase is detected in the structure. The remanence (Br) decreases with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). With the increase of substitution contents, the intrinsic coercivity (Hcj) increases, while the magnetic induction coercivity (Hcb) first increases, and then decreases. Br has a linear decreasing behavior with increasing temperature from 20 °C to 170 °C. Hcj raises linearly with increasing temperature from 20 °C to 170 °C. The average temperature coefficient of Br (αBr) basically remains constant with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). The average temperature coefficient of Hcj (αHcj) decreases with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). The electrical resitivity (ρ) decreases with increasing substitution content of Sm‐CrAl.

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Morphology and magnetic properties of pressed barium hexaferrite BaFe12O19 materials

Cited by 24 publications

References 29 publications

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

Nanoengineered High-Performance Hexaferrite Magnets by Morphology-Induced Alignment of Tailored Nanoplatelets

Synthesis, Magnetic and Electrical Characteristics of Ba‐Sr Hexaferrites Substituted with Samarium, Chromium and Aluminum

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