Thermal stability and glass forming ability of amorphous Hf2Co11B alloy

Musiał, A.; Śniadecki, Z.; Idzikowski, B.

doi:10.1016/j.matdes.2016.11.004

Cited by 18 publications

(4 citation statements)

References 39 publications

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“…It is worth mentioning that the magnetic measurements of the new compounds were performed on as-synthesized powder samples (micrometer-sized) obtained from crushing a bulk ingot without any further processing, hence the magnetic properties observed are purely intrinsic. Most of the REF magnetic materials discussed in the introduction, however, show their superior magnetic properties only in a highly processed state like ball-milling (particle size reduction), thin film production, sintering, melt-spinning, or densification. ,− These additional processing techniques can hugely improve the extrinsic magnetic hardness. For example, the high-temperature hard ferromagnetic Hf–Co and Zr–Co alloys were initially prepared using the same arc-melting technique that we have used.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, REF materials have intrinsically low SOC values and thus rely on improved extrinsic properties to increase H c . For example, controlling microstructure and domain orientation has led to appreciable results in Mn-based phases such as binary MnAl and MnBi − or phases from the systems Zr–Co and Hf–Co, − and L1 0 -ordered compounds, such as FeCo, CoPt, FeNi, − and α″-Fe 16 N 2 . These REF PMM have shown large coercivity ( H c values up to several hundred kA/m) and high-ordering temperatures (as high as ∼1000 K).…”

Section: Introductionmentioning

confidence: 99%

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Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)

et al. 2021

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Designing new rare-earth-free (REF) permanent magnetic materials (PMM) to replace the high performing but critically restrained rare-earth-based PMM remains a great challenge to the scientific community. Here, we report on the rational design of new REF PMM, Hf2 MIr5B2 (M = Fe, Mn) via a theory-experiment combined approach. Density functional theory (DFT) predicted strong interchain M-M spin-exchange coupling and large magnetocrystalline anisotropy energies (E MAE) for the new compounds, suggesting potential intrinsic PMM properties. Subsequent experimental bulk syntheses and magnetic characterizations established the highest ordering temperature (T C ∼ 900 K) for Hf2FeIr5B2 and the highest intrinsic coercivity (H C) value for Hf2MnIr5B2 (H C = 62.1 kA/m) reported to date for Ti3Co5B2-type compounds. Importantly, at room temperature both phases show significant coercivities due to intrinsic factors only, hinting at their huge potential to create REF PMM by improving extrinsic factors such as controlling the microstructure and the domain orientation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)

et al. 2021

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“…Annealing temperatures were close to the maxima of the first, second, and third crystallization stages and were determined by differential scanning calorimetry. X-ray diffraction (XRD) confirmed the existence of fully amorphous state [7,8]. Based on mentioned analysis, hard magnetic phase was identified as Hf 2 Co 11 with rhombohedral structure.…”

Section: Resultsmentioning

confidence: 96%

Development of Magnetic Properties during Annealing of Hf_2Co_{11}B Amorphous Alloy

2017

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Influence of heat treatment on magnetic properties of amorphous Hf2Co11B alloy was investigated. Hard magnetic phase, characterized by high magnetic anisotropy, appears during crystallization. The highest coercive field equal to 1.86 kOe, was obtained for sample annealed in third crystallization stage. Longer heat treatment at Ta = 650• C leads to decrease in coercive field, which can be the result of excess of the HfCo3B2 phase volume fraction and additionally eutectoid transformation of hard magnetic phase into soft magnetic Co23B6 and fcc-Co. Decrease of volume fraction of hard phase is confirmed by the remanence ratio mr. Value of mr, for Ta = 650• C, is decreasing with annealing time from 0.4 to 0.27 for 30 min and 120 min, respectively. The magnetocrystalline anisotropy constant K1 increases from 2.23 Merg/cm 3 for the amorphous ribbon to 15.84 Merg/cm 3 for the sample annealed at 650• C for 30 min.

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“…The experimental investigation on variation in wheel speed is reported only by McGuire et al on the synthesis of Hf 2 Co 11 B alloys to obtain magnetically hard nanocrystalline phases [11]. The crystallization process in Hf 2 Co 11 B melt-spun (MS) alloy at different heating rates is studied by Musial et al using DSC measurements and reported an enhanced glass-forming ability (GFA) in Hf-Co-B system [24]. A computational study based on Miedema's model reported a low GFA in Cr-Co-B system in comparison to Hf-Co-B system [25].…”

Section: Introductionmentioning

confidence: 99%

Influence of cooling rate on the magnetic properties of Hf–Co–Fe–B melt-spun alloy

2020

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In the present work, Hf 2 Co 9.5 Fe 1.5 B melt-spun (MS) alloy is synthesized by employing melt spinning at different wheel speeds viz. 16, 20, 24 and 28 m/s to study the effect of quenching on the thermal, structural, microstructural and magnetic properties. The phase purity and the magnetic behaviour of the MS ribbons are highly dependent on the cooling rate that is controlled by altering the tangential wheel speed during melt spinning. Cooling rates are found to increase with increase in wheel speed with a concurrent decrease in the ribbon thickness owing to the increase in the heat transfer coefficient at the thermal contact. The best phase purity and the magnetic properties are found for the ribbons melt-spun at 28 m/s. This could be attributed to the high cooling rate 2.3 × 10 7 K/s causing crystallization of hard magnetic Hf 2 Co 11 B phase leading to refined grain size. A maximum coercivity (H C ) ~ 2.18 kOe, remanence ratio (M r /M s ) ~ 0.61, an appreciable magnetic energy product (BH) max ~ 3 MGOe observed in the MS ribbons at 28 m/s illustrates the critical role of wheel speed in the enhancement of permanent magnetic properties in a single-step without annealing. XRD patterns reveal that the alloy was found to crystallize in orthorhombic Hf 2 Co 11 B in addition to cubic Co and Hf 6 Co 23 phases. FE-SEM analysis is carried out to realize the grain morphology and phase identification. The current work exhibits the efficacy of rapid quenching by melt spinning as an effective technique in the development of high-performance Hf 2 Co 9.5 Fe 1.5 B rare-earth-free permanent magnet alloy for future energy applications in the high-temperature regime.

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Thermal stability and glass forming ability of amorphous Hf2Co11B alloy

Cited by 18 publications

References 39 publications

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)

Development of Magnetic Properties during Annealing of Hf_2Co_{11}B Amorphous Alloy

Influence of cooling rate on the magnetic properties of Hf–Co–Fe–B melt-spun alloy

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Thermal stability and glass forming ability of amorphous Hf2Co11B alloy

Cited by 18 publications

References 39 publications

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-TC Hf2MIr5B2 (M = Mn, Fe)

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-TC Hf2MIr5B2 (M = Mn, Fe)

Development of Magnetic Properties during Annealing of Hf_2Co_{11}B Amorphous Alloy

Influence of cooling rate on the magnetic properties of Hf–Co–Fe–B melt-spun alloy

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Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)

Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High-T_C Hf₂MIr₅B₂ (M = Mn, Fe)