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Csizmadia E.,Magnetec Ungarn Kft. | Varga L.K.,Wigner Research Center for Physics | Palanki Z.,Magnetec Ungarn Kft. | Zamborszky F.,Magnetec Ungarn Kft.
Journal of Magnetism and Magnetic Materials | Year: 2015

Continuous stress annealing can be performed on FINEMET-type (Fe73.5Cu1Nb3Si15.5B7) ribbons. Here we report experiments conducted in a cheap open tubular furnace as a function of pulling velocity (v). We achieved up to v=120 m/min that is almost 100 times higher than previously reported for this kind of equipments. In this report we show for the first time how the properties are depending on the pulling velocity. While the achieved relative permeability μrremained constant without changing any other parameter than v, the elongation of the ribbon and the contraction of the ribbon width were monotonically changing as v was increased. The results support that the creep is not determined exclusively by the applied stress, but it is determined by the details of the amorphous-nanocrystalline transformation, which is influenced by the pulling velocity. The bigger the pulling velocity is, the higher the onset temperature of the amorphous-nanocrystalline transformation is, and the wider the associated exothermic peak is, resulting in increased elongation of the ribbon due to a short time formation of undercooled liquid state. © 2014 Elsevier B.V. Source


Eszenyi G.,Debrecen University | Bukki-Deme A.,Debrecen University | Harasztosi L.,Debrecen University | Zamborszky F.,Magnetec Ungarn Kft. | And 4 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2010

Barkhausen noise experiments, performed on different, heat treated FINEMET-type (Fe75Si15NbCu) ribbons, are discussed. The spectral density of the noise, measured under a constant magnetization rate, exhibits a definite change with the nanostructure of the ribbons. Thus mechanical sensitivities (δ) were compared with the Fourier spectra of the samples. It is found that the high and low frequency portions of the spectral density of the noise display a definite correlation with δ. This is similar to the one observed between the full dissipated Barkhausen noise energy of one exciting cycle and the mechanical sensitivity in our previous paper. Our results indicate that the investigation of the spectral density provides a rationale for non-destructive testing during industrial preparation of FINEMET-type materials. © 2009 Elsevier B.V. All rights reserved. Source


Halasz Z.,Magnetec Ungarn Kft. | Csizmadia E.,Magnetec Ungarn Kft. | Palanki Z.,Magnetec Ungarn Kft. | Zamborszky F.,Magnetec Ungarn Kft.
IEEE Transactions on Magnetics | Year: 2014

Soft magnetic cores made of nanocrystalline FINEMET-type Fe73,5Cu1Nb3Si15,5B7 ribbon have never been studied whether they are homogenous regarding their magnetic and mechanical properties. For small cores (i.e., cores with thin wall thickness), this is not so much in doubt as for heavy cores (e.g., ∼2 kg with 46 mm wall thickness). As it is well known, during the annealing process, this mass cannot be heated uniformly in normal industrial conditions, which causes differences regarding the magnetic and mechanical properties between the samples taken from various parts of the core. In this paper, we demonstrate that high inhomogeneity exists within a single toroidal core in terms of its magnetic properties. The measurement method and the experimental results are described in detail. © 2015 IEEE. Source


Zamborszky F.,Magnetec Ungarn Kft. | Toth D.,Magnetec Ungarn Kft. | Palanki Z.,Magnetec Ungarn Kft. | Csizmadia E.,Magnetec Ungarn Kft.
IEEE Transactions on Magnetics | Year: 2014

In this paper, we demonstrate two methods for measuring power losses of soft magnetic cores made of nanocrystalline (Fe100-a-bCoaNib)96-y-zCu1Nb3Si yBz alloys at the magnetic induction level Bmax = 300 mT and at the measurement frequency f = 100 kHz. We investigated the possible sources and consequences of measurement errors for the both electronic and simplified calorimetric methods. While the electrical core loss measurement showed more than a factor of 2 higher value for μr ∼ 300 sample than for μr ∼ 2600, the calorimetric method proved that it is not the case; it is only about 30% higher. This result is interpreted with significantly higher measurement uncertainty of the electrical measurement when the phase angle θ is very close to 90°, i.e., when the magnetic core behaves like an almost ideal inductor. The calorimetric measurement error is also gradually increasing as μr is lowered, due to the increasing fraction of the copper wire~{!/~}s Joule heating. The measured data are consistent with the eddy current loss component. It has been demonstrated that the tape thickness plays the most important role for the power loss of these soft magnetic cores. © 2014 IEEE. Source

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