scholarly journals Influence of Cu Content on Structure, Thermal Stability and Magnetic Properties in Fe72−xNi8Nb4CuxSi2B14 Alloys

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 726
Author(s):  
Tymon Warski ◽  
Adrian Radon ◽  
Przemyslaw Zackiewicz ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
...  

The effect of substitution of Fe by Cu on the crystal structure and magnetic properties of Fe72−xNi8Nb4CuxSi2B14 alloys (x = 0.6, 1.1, 1.6 at.%) in the form of ribbons was investigated. The chemical composition of the materials was established on the basis of the calculated minima of thermodynamic parameters: Gibbs free energy of amorphous phase formation ΔGamorph (minimum at 0.6 at.% of Cu) and Gibbs free energy of mixing ΔGmix (minimum at 1.6 at.% of Cu). The characteristic crystallization temperatures Tx1onset and Tx1 of the alpha-iron phase together with the activation energy Ea for the as-spun samples were determined by differential scanning calorimetry (DSC) with a heating rate of 10–100 °C/min. In order to determine the optimal soft magnetic properties, the wound cores were subjected to a controlled isothermal annealing process in the temperature range of 340–640 °C for 20 min. Coercivity Hc, saturation induction Bs and core power losses at B = 1 T and frequency f = 50 Hz P10/50 were determined for all samples. Moreover, for the samples with the lowest Hc and P10/50, the magnetic losses were determined in a wider frequency range 50 Hz–400 kHz. The real and imaginary parts of the magnetic permeability µ′, µ″ along with the cut-off frequency were determined for the samples annealed at 360, 460, and 560 °C. The best soft magnetic properties (i.e., the lowest value of Hc and P10/50) were observed for samples annealed at 460 °C, with Hc = 4.88–5.69 A/m, Bs = 1.18–1.24 T, P10/50 = 0.072–0.084 W/kg, µ′ = 8350–10,630 and cutoff frequency at 8–9.3 × 104 Hz. The structural study of as-spun and annealed ribbons was carried out using X-ray diffraction (XRD) and a transmission electron microscope (TEM).

1999 ◽  
Vol 577 ◽  
Author(s):  
M. Kopcewicz ◽  
A. Grabias ◽  
B. Idzikowski

ABSTRACTFormation of the nanocrystalline bcc Fe phase due to thermal treatment of the amorphous Fe80M7B12Cu1 (M: Ti, Ta, Nb, Mo) precursors is studied by the Mössbauer and differential scanning calorimetry techniques. The dependence of the formation of the bcc Fe phase on the alloy composition is discussed. In order to determine the optimal soft magnetic properties of these nanocrystalline alloys the rf-Mössbauer technique is used in which rf collapse effect induced by a radio-frequency (rf) magnetic field is employed. It was found that anisotropy fields in the nanocrystalline phase were smaller in Nb- and Mo-containing alloys as compared to the alloys which contain Ti or Ta. Variations of the anisotropy field vs. alloy composition and annealing temperature are discussed in detail.


2012 ◽  
Vol 465 ◽  
pp. 72-75
Author(s):  
Xiao Long Jiang ◽  
Y.J. Yao ◽  
M. Lai ◽  
K. Peng ◽  
Y.W. Du

A series of nanocrystalline FeNbB films were fabricated using ion-beam sputtering technique from FeNbB target. Pieces of these films were annealed for 1 hour at various temperatures up to 5730C. Room temperature soft magnetic properties of these films were measured. The influence of microstructure on magnetic behavior in nanocrystalline FeNbB films is investigated in a series of specimens with different film’s thickness. For the sample 120nm and 5000C annealed, cutoff frequency was found to be 5E7 Hz, which has the μf0=5E10.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1451 ◽  
Author(s):  
Tymon Warski ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
Przemyslaw Zackiewicz ◽  
Adrian Radon ◽  
...  

Influence of Cu content on thermodynamic parameters (configurational entropy, Gibbs free energy of mixing, Gibbs free energy of amorphous phase formation), crystallization kinetics, structure and magnetic properties of Fe86-xCuxB14 (x = 0, 0.4, 0.55, 0.7, 1) alloys is investigated. The chemical composition has been optimized using a thermodynamic approach to obtain a minimum of Gibbs free energy of amorphous phase formation (minimum at 0.55 at.% of Cu). By using differential scanning calorimetry method the crystallization kinetics of amorphous melt-spun ribbons was analyzed. It was found that the average activation energy of α-Fe phase crystallization is in the range from 201.8 to 228.74 kJ/mol for studied samples. In order to obtain the lowest power core loss values, the isothermal annealing process was optimized in the temperature range from 260 °C to 400 °C. Materials annealed at optimal temperature had power core losses at 1 T/50 Hz—0.13–0.25 W/kg, magnetic saturation—1.47–1.6 T and coercivity—9.71–13.1 A/m. These samples were characterized by the amorphous structure with small amount of α-Fe nanocrystallites. The studies of complex permeability allowed to determine a minimum of both permeability values at 0.55 at.% of Cu. At the end of this work a correlation between thermodynamic parameters and kinetics, structure and magnetic properties were described.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 304
Author(s):  
Jonghee Han ◽  
Jihyun Hong ◽  
Seoyeon Kwon ◽  
Haein Choi-Yim

In the Fe-Co alloy system, the addition of Cr improves the glass-forming ability (GFA) with superior soft magnetic properties such as high saturation magnetization (Ms) and low coercivity (Hc). In addition, Cr is considered to be an important factor for improving the corrosion resistance of Fe-based amorphous alloy. Therefore, in the present study, we investigated the GFA, soft magnetic properties, and corrosion resistance of the as-spun ribbons in [Co0.075Fe0.675B0.2Si0.05]100−xCrx (x = 0–8) alloy system. The ribbons were produced using the melt-spinning technique and were characterized by X-ray diffraction, differential scanning calorimetry, thermomechanical analysis, and vibrating sample magnetometer. The Co-Fe-B-Si-Cr alloys exhibited high thermal stability and a high Ms of 0.93–1.53 T. Corrosion properties were evaluated by cyclic voltammetry. The addition of Cr improved the corrosion resistance of the alloys. The alloys with a higher Cr content exhibited a higher corrosion resistance. The optimum combination with soft magnetic properties and corrosion resistance of Fe-co based amorphous alloys can be utilized for extensive fields of application through a variation of Cr contents.


Author(s):  
Man Zhu ◽  
Chi Zhang ◽  
Tao Xu ◽  
Lijuan Yao ◽  
Yongqin Liu ◽  
...  

Abstract The effects of additions of Co and Ni to the FeNbBCu alloys on the glass forming ability (GFA), soft magnetic properties and electrical resistivity of Fe-based amorphous alloys were studied by means of X-ray diffraction, differential scanning calorimetry, vibrating sample magnetometry and four-probe testing. The Fe80–x–y Nb5B14Cu1Co x Ni y alloys exhibit high thermal stability and excellent GFA with T x1 ≥ 735 K and T x1/T m ≥ 0.539. They also show excellent soft magnetic properties with high saturation magnetization of 93– 101 emu g–1 and low coercivity of 0.04 –2.37 Oe. The electrical resistivity of these alloys ranges from 121 μΩ cm to 163 μΩ cm. The newly developed FeNbBCu-CoNi glassy alloys not only possess good GFA and high thermal stability, but also have excellent magnetic properties, high electrical resistivity and low cost. With such promising properties, these alloys have potential for industrial applications.


1998 ◽  
Vol 22 (4_1) ◽  
pp. 186-189
Author(s):  
M. Matsumoto ◽  
A. Morisako ◽  
Y. Mutoh

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