Curie temperature behaviour at relaxation and nanocrystallization of Finemet alloys

Kaloshkin, S.D.; Churyukanova, M.; Zadorozhnyi, V. Yu.; Щетинин, И. В.; Roy, Rajat

doi:10.1016/j.jallcom.2011.01.090

Cited by 22 publications

(17 citation statements)

References 15 publications

(12 reference statements)

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“…This will cause inhomogeneity in the composition of the surrounding amorphous phase and the formation of local areas with different T c . 27,32,33 As proposed previously, the faster diffusing B atoms in the amorphous phase have a smooth concentration prole while the large slower Nb atoms accumulate sharply at the nanocrystalline grain boundaries. Therefore, the higher T c could be ascribed to Nb-poor and B-rich interior regions and the lower T c of the amorphous phase is related to regions near the grain boundaries with a high concentration of Nb atoms.…”

Section: Resultsmentioning

confidence: 54%

“…8 According to eqn (2) and the Bethe-Slater curve, at higher W s the average distance between Fe atoms will increase and thus the exchange interaction weakens. 27 This leads to the decrease of Curie temperature. Slight magnetization variations observed in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Besides, an enhancement of T c occurs. 27 The Curie temperature of the crystalline phase was also measured during the heating cycle of annealed ribbons in Fig. 9.…”

Section: Resultsmentioning

confidence: 99%

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On the effect of cooling rate during melt spinning of FINEMET ribbons

et al. 2013

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The effect of quenching wheel speed on the structure and Curie temperature of Fe73.5Si13.5B9Nb3Cu1 alloy has been investigated using X-ray diffraction, differential scanning calorimetry, transition electron microscopy and a SQUID magnetometer. Ribbons were melt-spun at different wheel speeds and then were annealed to nucleate nano crystals embedded in the amorphous matrix. The results indicated that the thickness of the ribbons was inversely proportional to the wheel speed following the power law of the type t∝V(s)(-1.231). DSC and XRD results showed that at higher wheel speeds the greater potential energy triggers the formation of Fe (Si) crystallites and thus, increases the crystallinity. TEM observations confirmed the presence of an α-Fe (Si) phase with ∼11 nm crystallite size in the amorphous matrix of annealed ribbons. Special emphasis was placed on the effect of the quenching wheel speed on the Curie temperature during the measurements. To this end, the magnetization variations versus temperature were studied before and after annealing. It was found that increasing the wheel speed results in the reduction of the Curie temperature in as-spun ribbons. Moreover, the Curie temperature of the intergranular amorphous region in the annealed ribbons was at least 80 °C higher than that of corresponding amorphous phase in as-spun ribbons due to exchange interaction penetration of the adjacent Fe (Si) crystallites and relaxation processes.

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

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On the effect of cooling rate during melt spinning of FINEMET ribbons

et al. 2013

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“…Thus the magnetic interactions in the amorphous phase determine the properties of the bulk material, which, however, have not been well studied. In this sense, a recent report [11] is instructive. By measuring the Curie temperature change in isochronally heattreated Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 alloy, two structural relaxations have been identified with activation energies E 1 ¼28 kJ/mol and E 2 ¼90 kJ/mol, respectively below and above the annealing temperature of 460 1C.…”

Section: Nanocrystalline Materialsmentioning

confidence: 93%

“…The work of Ref. [11], therefore, adds another dimension to the modification of the properties of a nanocrystalline material.…”

Section: Nanocrystalline Materialsmentioning

confidence: 99%

Advances in amorphous and nanocrystalline materials

Hasegawa

2012

Journal of Magnetism and Magnetic Materials

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Effects of chemical composition on nanocrystallization kinetics, microstructure and magnetic properties of finemet-type amorphous alloys

et al. 2013

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In this study, the kinetics of nanocrystallization of amorphous Fe73.5Si13.5B9Nb3Cu1 (F1) and Fe77Si11B9Nb2.4Cu0.6 (F2) alloys is investigated. The microstructure and magnetic properties of the nanocrystalline alloys are compared. The crystallization temperature of F2 alloy is shifted towards lower temperatures with respect to F1. Thus, the crystalline volume fraction and the crystalline grain size at specific annealing temperature for the F2 alloy are higher than for the F1 alloy, accounting for the higher coercive force of F2 alloy with respect to the one of F1 alloy. According to isoconversional methods, the activation energy for crystallization is variable as a function of transformed fraction because of the continuous changes in chemical composition during the transformation. Mean values of 350 and 290 kJ/mol are obtained for F1 and F2, respectively. Microstructural observations confirm that minor changes in chemical composition affect the kinetics and final microstructure of the nanocrystalline alloy, that determine the observed magnetic properties

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Curie temperature behaviour at relaxation and nanocrystallization of Finemet alloys

Cited by 22 publications

References 15 publications

On the effect of cooling rate during melt spinning of FINEMET ribbons

On the effect of cooling rate during melt spinning of FINEMET ribbons

Advances in amorphous and nanocrystalline materials

Effects of chemical composition on nanocrystallization kinetics, microstructure and magnetic properties of finemet-type amorphous alloys

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