Nikolai Nikul'chenkov
@imp.uran.ru
M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences
RESEARCH, TEACHING, or OTHER INTERESTS
Metals and Alloys, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Computer Science Applications
Scopus Publications
Scopus Publications
Mikhail L. Lobanov, Nikolai N. Nikul’chenkov, Vladimir V. Popov, Artem S. Yurovskikh, Mikhail Yu. Veksler, and Vladimir I. Pastukhov
MDPI AG
Ceramic insulation coating (glass film) is an important constituent of grain-oriented electrical steel (GOES) designed for use in transformers. Within the scope of this study, the glass film was obtained by means of interaction between the surface of GOES containing 0.5 wt. % Cu and a heat-resistant MgO coating during annealing up to 1100 °C in the 75%H2 + 25%N2 atmosphere. The structure of glass film was analyzed using X-ray diffraction, glow-discharge optical emission spectroscopy, scanning probe microscopy, scanning electron microscopy, differential scanning calorimetry and thermodynamic calculations. After annealing, the glass film contained the following phases: crystalline (MgFe)2SiO4 and amorphous Fe-based solid solutions. The multi-stage mechanism of the glass film formation on GOES surface during high-temperature annealing was determined.
D. A. Krivenok, S. V. Danilov, N. N. Nikul’chenkov, and M. L. Lobanov
AIP Publishing
N. Nikul’chenkov and M. Lobanov
Elsevier BV
S. V. Danilov, K. B. Maslennikov, N. V. Urtsev, N. N. Nikul’chenkov, and M. L. Lobanov
AIP Publishing
N. N. Nikul'chenkov, A. B. Loginov, S. V. Danilov, and B. A. Loginov
AIP Publishing
N. N. Nikul'chenkov, P. L. Reznik, and M. L. Lobanov
AIP Publishing
The solid-state amorphization process was observed on Fe–3%Si–0.5%Cu alloy surface coated by MgO. The observation was performed using non-ambient x-ray diffraction analysis during continuous annealing at 600–1060 °C. Also, scanning electron microscopy was used with electron backscatter diffraction and electron microprobe analysis. The mechanism of amorphous phase formation was proposed based on the analysis of reactions between MgO, H2O (gas), H2, SiO2, Fe–3%Si (solid solution). The reactions occur at glass film formation during high-temperature annealing of Fe– 3%Si–0.5%Cu. The hydrogen reduces Mg2Si then it transfers into Fe(Si) solid solution with amorphization.
Mikhail Lobanov, Artem Yurovskikh, Pavel Reznik, Nikolai Nikul’chenkov, German Rusakov, and Andrey Redikul’tsev
Institute for Metals Superplasticity Problems of RAS
The study of the processes occurring in the surface layer of the MgO coated commercial alloy Fe-3 %Si-0.5 %Cu (grain oriented electrical steel) demonstrated that the amorphous phase in the form of a Fe-based solid solution is formed during continuous heating in the 95 %N 2 + 5 %H 2 atmosphere. For the purposes of this study, the following methods were used: non-ambient XRD at 20 –1060°C with heating and cooling at a rate of 0.5 dps, layer-by-layer chemical analysis performed by a glow discharge analyzer, scanning electron microscopy and energy dispersive X-ray spectroscopy. ThermoCalc software was used to calculate the potential phase equilibrium states. The amorphous phase was formed in the α → γ transformation temperature range, when the heating rates were altered in the surface layer of 1 µm initially consisted of a solid α-Fe-based solution with ~1– 2 wt.% Si with (MgFe) 2 SiO 4 , (MgFe)O, SiO 2 oxide inclusions. We suppose that (MgFe) 2 SiO 4 oxides are partly reduced by H 2 to Mg 2 Si molecular complexes, which become solid solutions in the temperature range of the metastability of the α-Fe crystal lattice with subsequent amorphization as an alternative to the α → γ transition. The amorphous state is obtained at 920 – 960°C and is retained both at subsequent heating (to 1060°C) and cooling (to 20°С), which is super-stable compared to the established metallic glasses. The composition of the amorphous phase can be described by the formula Fe 89.5 Si 6 Mg 4 Cu 0.5 .
Nikolai N. Nikulchenkov, Konstantin Ye. Cherepanov, and Mikhail L. Lobanov
Trans Tech Publications, Ltd.
Thermophysical parameters of Finemet-type initially amorphous alloy produced using rapid quenching technique were determined. The temperature intervals of phase and structure changes have been obtained using calorimetry and non-ambient X-ray diffraction methods. The electric resistance data were recalculated to alloy electrical conductivity which it was recalculated to heat conductivity using the Wiedemann–Franz law. Resulting parameters were used for heat processes simulation that occurs in amorphous material of built-up transformer core during annealing in nanocrystallization temperature interval. Heat treatment of different sizes twisted magnetic cores was optimized.
N. N. Nikul’chenkov, S. V. Danilov, K. E. Cherepanov, and M. L. Lobanov
AIP Publishing
Nikolai Nikul’chenkov, Artem Yurovskikh, Yuri Starodubtsev, and Mikhail Lobanov
Institute for Metals Superplasticity Problems of RAS
Благодарности/Acknowledgements. Авторы выра‑ жают признательность за содействие программе под‑ держки ведущих университетов РФ в целях повышения их конкурентоспособности № 211 Правительства РФ № 02. А03.21.0006. Исследование выполнено при финан‑ совой поддержке РФФИ в рамках научного проекта №19‑08‑00071./The work was financially supported by the RF Government, No. 211 (contract No. 02. A03.21.0006). The reported study was funded by RFBR according to the research project №19‑08‑00071.
N. N. Nikul’chenkov, A. S. Yurovskikh, and M. L. Lobanov
National University of Science and Technology MISiS
Critical points of amorphous alloy of Fe – Si – Nb – Cu – Mo – B system was determined using the non-ambient x-ray diffraction method. The sample with amorphous structure was produced by planar flow casting process. Temperature range of alloy nanocrystalline state was established
GRANT DETAILS
Russian Foundation for Basic Research "Aspiranty", 2020-2022, An Obtaining of the Thermostable Amorphous State Triggered by α-γ-transformation in the Alloys Based on the Fe-Si-Mg System, Co-Investigator
RESEARCH OUTPUTS (PATENTS, SOFTWARE, PUBLICATIONS, PRODUCTS)
Lobanov M. L., Nikul’chenkov N.N., Yurovskikh A.S., Zorina M. A., Veksler M.Y., Amorphous Magnetic Alloy Based on The Iron-Silicon Syatem. Russia. RU2791679. Date of publication: 13.03.2023