scholarly journals Influence of Cu Content on Structure and Magnetic Properties in Fe86-xCuxB14 Alloys

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1451 ◽  
Author(s):  
Tymon Warski ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
Przemyslaw Zackiewicz ◽  
Adrian Radon ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Free Energy ◽  
Thermodynamic Parameters ◽  
Gibbs Free Energy ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Crystallization Kinetics ◽  
Core Loss ◽  
Cu Content ◽  
Amorphous Phase Formation

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.

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 ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Free Energy ◽  
Gibbs Free Energy ◽  
Cutoff Frequency ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Scanning Calorimetry ◽  
Cu Content ◽  
Iron Phase ◽  
Free Energy Of Mixing

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).

Thermodynamic aspects of amorphous phase formation

1986 ◽  
Vol 1 (1) ◽  
pp. 38-46 ◽  
Author(s):  
N. Saunders ◽  
A. P. Miodownik
Keyword(s):  
Free Energy ◽  
Solid State ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Vapor Deposition ◽  
Solid State Reaction ◽  
Temperature Stability ◽  
Temperature Liquid ◽  
Amorphous Phase Formation ◽  
Alloy Systems

The glass-forming ability of the three alloy systems Co–Zr, Cu–Zr, and Ni–Zr has been analyzed for three distinct production routes: (1) liquid quenching, (2) vapor deposition, and (3) solidstate reaction. Using the free energy and heats of formation curves obtained from the thermodynamic characterization of the respective alloy systems, a satisfactory rationale can be obtained for amorphous phase formation by all three routes. The analysis shows that while amorphous phase formation by quenching from the high-temperature liquid is clearly dependent on factors such as quench rate and the value TG/TM, it is the low-temperature stability of the amorphous phase relative to the other crystalline structures that enables amorphous phases to be formed by both vapor deposition and solid-state reaction. The underlying free energy curves indicate the interesting possibility of a supersaturation sequence in the nucleation of an amorphous phase by solid-state reaction. The principles underlying thermodynamic characterizations are briefly discussed, and a characterization for Co–Zr is presented.

Amorphous phase formation in irradiated intermetallic compounds

1983 ◽  
Vol 77 (3-4) ◽  
pp. 273-293 ◽  
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
L. A. Charlot
Keyword(s):  
Intermetallic Compounds ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Amorphous Phase Formation

Amorphous Phase Formation During Ion Mixing of Ti/Si Bilayers at Elevated Temperature

1988 ◽  
Vol 100 ◽  
Author(s):  
K. Maex ◽  
R. F. De Keersmaecker ◽  
M. Van rossum ◽  
W. F. Van Der Weg
Keyword(s):  
Elevated Temperature ◽  
Thermal Treatment ◽  
Diffusion Couple ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Multilayer Structure ◽  
Elevated Temperatures ◽  
Binary Diffusion ◽  
Amorphous Phase Formation

ABSTRACTThe amorphous phaseformation in Ti-Si bilayers upon ion mixing at elevated temperatures and in Ti-Si multilayers upon thermal treatment was studied. In the case of ion mixing with 5×1015 cm−2 Xe atoms at temperatures around 240°C a 100nm thick amorphous Ti-Si alloy is formed with a very homogeneous Ti:Si=3 :4 composition. Thermal treatment of the Ti-Si multilayer structure at similar temperatures also yields amorphous silicide layers. The results are interpreted according to the evolution in a planar binary diffusion couple, where the Si and Ti concentrations in the reacted layer are dictated by thermodynamic and kinetic arguments.

Absorption Equilibrium and Thermodynamics of Fenugreek Yellow Pigment on Macroporous Resins

2011 ◽  
Vol 233-235 ◽  
pp. 91-94
Author(s):  
Feng Han ◽  
Wen Hong Li ◽  
Xuan Tang ◽  
Dong Li
Keyword(s):  
Free Energy ◽  
Thermodynamic Parameters ◽  
Gibbs Free Energy ◽  
Adsorption Equilibrium ◽  
Yellow Pigment ◽  
Adsorption Models ◽  
Freundlich Model ◽  
Langmuir Adsorption ◽  
Macroporous Resins ◽  
Equilibrium Data

The adsorption equilibrium and thermodynamics of pigment extracted from Fenugreek after degumming on macroporous resins was investigated under differentinitial concentrations. The suitability of the Freundlich and Langmuir adsorption models to the equilibrium data was investigated. The model fitness was determined by R2 . Thermodynamic parameters were calculated by the Van’t Hof equation.The results showed that Freundlich model gave a better fit of adsorption isotherms than Langmuir models. The positive value of enthalpy(∆H) indicated that the adsorption was endothermic, the negative value of Gibbs free energy (∆G) showed the spontaneous and favoured nature of adsorption, and the entropy(∆S) was positive.The resins LS-46 showed an effective adsorbtion for Fenugreek yellow pigment.

Amorphous phase formation and stability in W-Ti-Si metallization materials

1986 ◽  
Vol 21 (11) ◽  
pp. 4029-4034 ◽  
Author(s):  
R. K. Ball ◽  
W. G. Freeman ◽  
A. J. Taylor ◽  
A. G. Todd
Keyword(s):  
Amorphous Phase ◽  
Phase Formation ◽  
Amorphous Phase Formation
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