Phase selection and nanocrystallization in Cu-free soft magnetic FeSiNbB amorphous alloy upon rapid annealing

Morsdorf, Lutz; Pradeep, Konda Gokuldoss; Herzer, G.; Kovács, András; Dunin-Borkowski, Rafal E.; Povstugar, Ivan; Коныгин, Г. Н.; Choi, Pyuck‐Pa; Raabe, Dierk

doi:10.1063/1.4944595

Cited by 15 publications

(4 citation statements)

References 21 publications

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“…Comparable grain size on the order of %5 nm has been reported in the literature by flash annealing techniques using preheated Cu blocks. [28][29][30][31] The fact that such grain refinement is achieved by means of in-line susceptor-based RF induction provides a viable and attractive pathway toward scalable manufacturing techniques for thermal processing of amorphous and nanocrystalline alloys leveraging electromagnetic field-assisted processing methods.…”

Section: Resultsmentioning

confidence: 99%

Radio‐Frequency Rapid Thermal Processing Enabling Spatial Phase Transformation and Nanocrystallization of Soft Magnetic Amorphous Alloys

et al. 2022

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Thermal processing of soft magnetic amorphous and nanocrystalline alloys is explored under the influence of radio‐frequency induction‐heating techniques. Direct induction‐heating concepts based on longitudinal and transverse flux heating are examined and the details of electromagnetic fields interaction with metallic strips are discussed by analytical calculations as well as finite element analysis. Initial experimental results confirming spatial control of phase transformations and nanocrystallization within a single strip of Finemet Fe‐based amorphous ribbons are reported. The degree to which primary and secondary crystallization temperature are achieved depends on the spacing between the ribbon relative to the induction coil as well as the coil design and configuration. For transverse coil configurations, the local temperature and therefore microstructural evolution is different across the lateral dimension of processed ribbons, with reduced gap sizes producing enhanced peak temperatures and larger temperature distributions with greater spatial variation in microstructure. In addition, indirect susceptor‐based induction heating under tension is performed and the impact of microstructure is demonstrated. Herein, potential for exploiting spatially optimized phase transformations is illustrated through electromagnetic field–assisted processing in a scalable manufacturing process with amorphous and nanocrystalline soft magnetic alloys.

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Section: Resultsmentioning

confidence: 99%

Radio‐Frequency Rapid Thermal Processing Enabling Spatial Phase Transformation and Nanocrystallization of Soft Magnetic Amorphous Alloys

et al. 2022

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“…Relaxation upon isothermal annealing below the crystallization transition temperature is applied to release the residual stress in metallic amorphous alloys [ 10 ] to enhance their soft magnetic performance [ 8 ]. Ordinarily, the soft magnetic properties of amorphous alloys can be further optimized through appropriate annealing characteristics, such as the annealing temperature, heating rate and holding time [ 11 ]. As-spun amorphous ribbons are usually subjected to magnetic field annealing to improve their soft magnetic properties (SMPs) [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Annealing on the Soft Magnetic Properties and Microstructure of Fe82Si2B13P1C3 Amorphous Iron Cores

Zheng

Zhang

et al. 2023

Materials

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This research paper investigated the impact of normal annealing (NA) and magnetic field annealing (FA) on the soft magnetic properties and microstructure of Fe82Si2B13P1C3 amorphous alloy iron cores. The annealing process involved various methods of magnetic field application: transverse magnetic field annealing (TFA), longitudinal magnetic field annealing (LFA), transverse magnetic field annealing followed by longitudinal magnetic field annealing (TLFA) and longitudinal magnetic field annealing followed by transverse magnetic field annealing (LTFA). The annealed samples were subjected to testing and analysis using techniques such as differential scanning calorimetry (DSC), transmission electron microscopy (TEM), X-ray diffraction (XRD), magnetic performance testing equipment and magneto-optical Kerr microscopy. The obtained results were then compared with those of commercially produced Fe80Si9B11. Fe82Si2B13P1C3 demonstrated the lowest loss of P1.4T,2kHz = 8.1 W/kg when annealed in a transverse magnetic field at 370 °C, which was 17% lower than that of Fe80Si9B11. When influenced by the longitudinal magnetic field, the magnetization curve tended to become more rectangular, and the coercivity (B3500A/m) of Fe82Si2B13P1C3 reached 1.6 T, which was 0.05 T higher than that of Fe80Si9B11. During the 370 °C annealing process of the Fe82Si2B13P1C3 amorphous iron core, the internal stress in the strip gradually dissipated, and impurity domains such as fingerprint domains disappeared and aligned with the length direction of the strip. Consequently, wide strip domains with low resistance and easy magnetization were formed, thereby reducing the overall loss of the amorphous iron core.

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“…Recently, a high heating rate above 100 K/s was realized by using a pair of preheated Cu blocks for annealing [18,19]. This rapid heating technique opens the possibility for significant reductions of nonmagnetic additives in Fe-based nanocrystalline soft magnetic alloys because the grain refinement is promoted by the heating process.…”

Section: Introductionmentioning

confidence: 99%

Effect of heating rate during primary crystallization on soft magnetic properties of melt-spun Fe-B alloys

et al. 2017

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Phase selection and nanocrystallization in Cu-free soft magnetic FeSiNbB amorphous alloy upon rapid annealing

Abstract: Investigation on the crystallization mechanism difference between FINEMET® and NANOMET® type Fe-based soft magnetic amorphous alloys

Cited by 15 publications

References 21 publications

Radio‐Frequency Rapid Thermal Processing Enabling Spatial Phase Transformation and Nanocrystallization of Soft Magnetic Amorphous Alloys

Radio‐Frequency Rapid Thermal Processing Enabling Spatial Phase Transformation and Nanocrystallization of Soft Magnetic Amorphous Alloys

The Effect of Annealing on the Soft Magnetic Properties and Microstructure of Fe82Si2B13P1C3 Amorphous Iron Cores

Effect of heating rate during primary crystallization on soft magnetic properties of melt-spun Fe-B alloys

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