scholarly journals Structural, Thermal and Magnetic Analysis of Fe75Co10Nb6B9 and Fe65Co20Nb6B9 Nanostructured Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4542
Author(s):  
Albert Carrillo ◽  
Jason Daza ◽  
Joan Saurina ◽  
Lluisa Escoda ◽  
Joan-Josep Suñol

Two nanocrystalline ferromagnetic alloys of the Fe-Co-Nb-B system have been produced by mechanical alloying (MA). Their microstructure, thermal behavior and magnetic response were checked by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). After 80 h of MA, the alloys were nanostructured (bcc-Fe(Co)-rich phase). As the Co content increases, the density of the dislocations decreases. Besides, a higher concentration of Co causes an increase in the activation energy of the crystallization process. The calculated energies, 267 and 332 kJ/mol, are associated to the crystalline growth of the bcc-Fe-rich phase. The Co content of the samples has no effect on the value of the saturation magnetization, whereas the coercivity is lower in the alloy containing less Co. Samples were compacted and heat-treated. Optimal annealing reduces the coercivity by a factor of two. Results were compared with the data of Fe-Nb-B and Fe-Ni-Nb-B alloys.

2011 ◽  
Vol 399-401 ◽  
pp. 869-872
Author(s):  
Bin Li ◽  
Hai Feng Chen ◽  
Li Hua Wen ◽  
Chen Ma

Ag2O-CaO-Fe2O3-SiO2glass-ceramic was prepared by the sol-gel method. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used to investigate crystallization process of Ag2O-CaO-Fe2O3-SiO2glass. The kinetic results show that the values of the activation energy and frequency factor of the glass are 441.991 KJ/ mol and 1.58×1020, respectively. And the dimensionality of crystal growth, n, decreases as the heating rate increases. The crystalline phases of the glass-ceramic are magnetite, wollastonite and minor hematite. The saturation magnetization and coercive force of the heat-treated glass are 0.08 Wb/m2and 14 KA/m at room temperature. The glass-ceramic has some capacity of anti-microbial.


2012 ◽  
Vol 535-537 ◽  
pp. 950-953
Author(s):  
Li Na Bai ◽  
Gui Xing Zheng ◽  
Zhi Jian Duan ◽  
Jian Jun Zhang

The influences of Gd concentration on martensitic transformation and magnetic properties of NiMnIn alloys were investigated by differential scanning calorimetry (DSC) , vibrating sample magnetometry (VSM), X-ray diffraction (XRD) and etc. It is Observed through the experiment: the addition of Gd enhances martensite transition temperature;X-ray diffraction analysis of experimental alloys is revealed that to the mixture is martensite and austenite at room temperature; content of Gd is not proportional to the improvement of magnetic property.


2018 ◽  
Vol 10 (6) ◽  
pp. 181
Author(s):  
Arif Budiman ◽  
Sandra Megantara ◽  
Putri Raraswati ◽  
Tazyinul Qoriah

Objective: The aim of this study was to develop a solid dosage form of glibenclamide with increasing the solubility properties of glibenclamide with cocrystallization method.Methods: Virtual screening was performed to investigate the interaction between glibenclamide and a co-former. Saccharin, the selected co-former, then co-crystallized with glibenclamide with equimolar ratios of 1:1 and 1:2 using the solvent evaporation method. Further characterization was performed using an infra-red (IR) spectrophotometer, differential scanning calorimetry (DSC), and powder x-ray diffraction (PXRD).Results: Co-crystals of 1:2 equimolar ratio were more highly soluble compared to pure glibenclamide (30-fold for 12 h and 24-fold for 24 h). The dissolution rate had also increased from 46.838% of pure glibenclamide to 77.655% of glibenclamide co-crystal in 60 min. There was no chemical reaction observed during the co-crystallization process based on the IR spectrum. However, there was a new peak in the X-Ray diffractogram and a reduction of melting point in the DSC curve, indicating the formation of co-crystals.Conclusion: The optimal co-crystal ratio of glibenclamide-saccharin was found to be 1:2, which was successful in improving the solubility of glibenclamide.


2019 ◽  
Vol 75 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Avantika Hasija ◽  
Deepak Chopra

The concomitant occurrence of dimorphs of diphenyl (3,4-difluorophenyl)phosphoramidate, C18H14F2NO3P, was observed via a solution-mediated crystallization process with variation in the symmetry-free molecules (Z′). The existence of two forms, i.e. Form I (block, Z′ = 1) and Form II (needle, Z′ = 2), was characterized by single-crystal X-ray diffraction, differential scanning calorimetry and powder X-ray diffraction. Furthermore, a quantitative analysis of the energetics of the different intermolecular interactions was carried out via the energy decomposition method (PIXEL), which corroborates with inputs from the energy framework and looks at the topology of the various intermolecular interactions present in both forms. The unequivocally distinguished contribution of strong N—H...O hydrogen bonds along with other interactions, such as C—H...O, C—H...F, π–π and C—H...π, mapped on the Hirshfeld surface is depicted by two-dimensional fingerprint plots. Apart from the major electrostatic contribution from N—H...O hydrogen bonds, the crystal structures are stabilized by contributions from the dispersion energy. The closely related melting points and opposite trends in the calculated lattice energies are interesting to investigate with respect to the thermodynamic stability of the observed dimorphs. The significant variation in the torsion angles in both forms helps in classifying them in the category of conformational polymorphs.


2012 ◽  
Vol 569 ◽  
pp. 297-300 ◽  
Author(s):  
Wei Wang ◽  
Yong Xian Liu ◽  
Xiang Dong Shi ◽  
Jin Hua Li ◽  
J.Y.H. Fuh

This research focused on the synthesis and investigation of the thermal properties and microstructure of the Al2O3/SiO2 /ZrO2 system applied to dental field. The composite ceramic was studied by scanning electron microcopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Detailed investigations of the different proportions of materials on the preparation and microstructural phases of ternary eutectic were presented. Furthermore, the crystallization process was investigated by using DSC and XRD. The results indicate that sintering microstructure of the ternary eutectic composite is greatly influenced by the materials proportions. The synthetically thermal analysis shows that the eutectic temperature of ternary Al2O3/SiO2 /ZrO2 composite is 1040°C, is well matching the phase diagram of Al2O3/SiO2 /ZrO2.


1990 ◽  
Vol 192 ◽  
Author(s):  
S.J. Jones ◽  
W.A. Turner ◽  
D. Pang ◽  
W. Paul

ABSTRACTResults from structural measurements on r.f. glow discharge produced a-Ge:H films have been found to be substrate dependent. The variations in the results were found to depend on both the substrate temperature, Ts, and the substrate yield strength. Differential scanning calorimetry results were particularly affected by these parameters. For films prepared at Ts = 150°C, the DSC spectra contain two exothermic peaks when the films are deposited on low yield strength substrates while only one exothermic peak is present for films deposited on high yield strength substrates. One exothermic DSC peak is seen in spectra for all films prepared at Ts = 300°C no matter what substrates were used. This DSC spectral dependence is attributed to differences in the microstructure of films deposited at the two substrate temperatures, as seen in TEM micrographs. X-ray diffraction measurements performed on films annealed to various temperatures show that all of the exothermic DSC peaks described above are associated with the crystallization process. Thus, for the films prepared at low Ts, crystallization is either a one or two step process depending on the yield strength of the substrate.


Author(s):  
C. G. McKamey ◽  
D. M. Kroeger ◽  
D. S. Easton ◽  
J. A. Horton

In a previous paper the results of a study of the crystallization of Zr-Ni metallic glasses of compositions between 55 and 70 at. % Zr were reported. Data from differential scanning calorimetry (DSC) and x-ray diffraction (XRD) were presented and discussed with respect to the phase transformations occurring during the crystallization process. A metastable crystalline phase, shown by DSC and XRD results to appear between 57 and 63.2 at. % Zr, was the first phase to appear upon heating the amorphous metal. (Evidence indicates the stoichiometric composition for this phase is approximately 60% Zr.) This metastable phase transforms to the equilibrium crystalline phases (ZrNi and Zr2Ni) upon further heating. For compositions of 55-57 and 63.5-70% Zr only the equilibrium phases appear upon heating. It was noted that phase separation and chemical short range ordering (SRO) are believed to play an important role in the crystallization of these alloys.


Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 443
Author(s):  
Francisco G. Cuevas ◽  
Sergio Lozano-Perez ◽  
Rosa María Aranda ◽  
Raquel Astacio

The crystallization process, both at the initial and subsequent stages, of amorphous Al88-RE4-Ni8 alloys (RE = Y, Sm and Ce) has been studied. Additionally, the consequences of adding 1 at.% Cu replacing Ni or Al were studied. The stability of the amorphous structure in melt spun ribbons was thermally studied by differential scanning calorimetry, with Ce alloys being the most stable. The effect of Cu to reduce the nanocrystal size during primary crystallization was analyzed by transmission electron microscopy. This latter technique and x-ray diffraction showed the formation of intermetallic phases at higher temperatures. A clear difference was observed for the Ce alloy, with a simpler sequence involving the presence of Al3Ni and Al11Ce3. However, for the Y and Sm alloys, a more complex evolution involving metastable ternary phases before Al19RE5Ni3 appears, takes place. The shape of the intermetallics changes from equiaxial in the Ce alloys to elongate for Y and Sm, with longer particles for Sm and, in general, when Cu is added to the alloy.


2012 ◽  
Vol 535-537 ◽  
pp. 959-963
Author(s):  
Li Na Bai ◽  
Gui Xing Zheng ◽  
Jing Xin ◽  
Jian Jun Zhang

The influences of Gd concentration on martensitic transformation and magnetic properties of NiMnIn alloys were investigated by differential scanning calorimetry (DSC) , vibrating sample magnetometry (VSM), X-ray diffraction (XRD) and etc. It shows that addition of Gd enhances martensite transition temperature and that X-ray diffraction analysis of experimental alloys is revealed which the mixture is martensite and austenite at room temperature. These alloys show promise as a metamagnetic shape memory alloy with magnetic-field-induced shape memory effect.


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