scholarly journals Theoretical and Experimental Parameters of the Structure and Crystallization Kinetics of Melt-Quenched As30Te64Ga6 Glassy Alloy

2021 ◽  
Author(s):  
Abdelazim M. Mebed ◽  
Meshal Alzaid ◽  
R.M. Hassan ◽  
Alaa Abd-Elnaiem
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Kinetic Parameters ◽  
Crystallization Kinetics ◽  
Glassy Alloy ◽  
Characteristic Temperature ◽  
Nominal Composition ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Kinetics Of

Abstract The present framework reports the structural, fundamental parameters, and crystallization kinetics of the melt-quenched As30Te64Ga6 chalcogenide glass. The energy dispersive X-ray analysis of the As30Te64Ga6 glassy system reveals that the constituent element ratio of the investigated bulk sample agrees with the nominal composition. Also, X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to characterize crystallization kinetics, and structural properties; respectively. Four characteristic temperatures related to various phenomena are observed in the investigated DSC traces. The first one is Tg that corresponds to the glass transition temperature. The second one is TC1, and TC2 that corresponds to the onset of the double crystallization temperatures. The third one TP1, and TP2 identifies the double peak crystallization temperatures. The last characteristic temperature Tm is the melting point. The XRD analysis indicates the amorphous structure of the as-prepared glassy alloy, while the annealed samples are polycrystalline. The crystallization kinetics of the As30Te64Ga6 bulk are studied under non-isothermal conditions. In addition, the values of various kinetic parameters such as the glass transition activation energy, weight stability standard, and Avrami support were determined. The activation energy of the crystallization process for As30Te64Ga6 glass alloy was calculated using classical methods. The results indicated that the rate of crystallization is related to thermal stability and the ability to form glass. Kinetic parameters have been estimated with some conventional methods and found to be dependent on heating rates (β).

Study on Curing Kinetics of MEP-15/593/660 System

2014 ◽  
Vol 988 ◽  
pp. 31-35
Author(s):  
Jia Le Song ◽  
Chan Chan Li ◽  
Zhi Mi Zhou ◽  
Chao Qiang Ye ◽  
Wei Guang Li
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Kinetic Parameters ◽  
Curing Kinetics ◽  
Conversion Ratio ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Curing Kinetic ◽  
The Relationship ◽  
Kinetics Of

Curing kinetics of MEP-15/593 system and MEP-15/593/660 system is studied by means of differential scanning calorimetry (DSC). Curing kinetic parameters are evaluated and the relationship between diluent 660 and the curing properties is investigated. The results show that the diluent 660 can not only reduce viscosity and activation energy, but also improve the degree of cure and conversion ratio.

Non-Isothermal Crystallization Kinetics of Mg61Zn35Ca4 Glassy Alloy

2017 ◽  
Vol 898 ◽  
pp. 657-665
Author(s):  
Dao Zhang ◽  
Wang Shu Lu ◽  
Xiao Yan Wang ◽  
Sen Yang
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Melt Spinning ◽  
Glassy Alloy ◽  
Heating Rates ◽  
Isothermal Crystallization Kinetics ◽  
Complex Process ◽  
Activation Energy Of Crystallization ◽  
Kinetics Of

The non-isothermal crystallization kinetics of Mg61Zn35Ca4 glassy alloy prepared via melt-spinning were studied by using isoconversion method. The crystalline characterization of Mg61Zn35Ca4 was examined by X-ray diffraction. Different scanning calorimeter was used to investigate the non-isothermal crystallization kinetics at different heating rates (3-60 K/min). The calculated value of Avrami exponent obtained by Matusita method indicated that the crystalline transformation for Mg61Zn35Ca4 is a complex process of nucleation and growth. The Kissinger-Akahira-Sunose method was used to investigate the activation energy. The activation energy of crystallization varies with the extent of crystallization and hence with temperature. The Sestak-Berggren model was used to describe the non-isothermal crystallization kinetics.

Crystallization kinetics of amorphous Ga–Sb–Te chalcogenide films: Part I. Nonisothermal studies by differential scanning calorimetry

2004 ◽  
Vol 19 (10) ◽  
pp. 2929-2937 ◽  
Author(s):  
Chain-Ming Lee ◽  
Yeong-Iuan Lin ◽  
Tsung-Shune Chin
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Kinetics ◽  
Crystallization Temperature ◽  
Ternary Phase Diagram ◽  
Film Deposition ◽  
Rate Dependency ◽  
Scanning Calorimetry ◽  
Kinetics Parameters ◽  
Kinetics Of

Nonisothermal crystallization kinetics of amorphous chalcogenide Ga–Sb–Te films with compositions along the pseudo-binary tie-lines connecting Sb7Te3−GaSb and Sb2Te3–GaSb of the ternary phase diagram were investigated by means of differential scanning calorimetry. Powder samples were prepared firstly by film deposition using a co-sputtering method; the films were then stripped from the substrate. The activation energy (Ea) and rate factor (Ko) were evaluated from the heating rate dependency of the crystallization temperature using the Kissinger method. The kinetic exponent (n) was deduced from the exothermic peak integrals using the Ozawa method. The crystallization temperature (Tx = 181 to 327 °C) and activation energy (Ea= 2.8 to 6.5 eV) increased monotonically with increasing GaSb content and reached a maximum value in compositions located at the vicinity of GaSb. The kinetic exponent is temperature dependent and shows higher values in the SbTe-rich compositions. Promising media compositions worthy of further studies were identified through the determined kinetics parameters.

Effect of Hyperbranched Polymer on Crystallization Kinetics of Isotactic Polypropylene

2012 ◽  
Vol 535-537 ◽  
pp. 1142-1145
Author(s):  
Guang Tian Liu ◽  
Jing Lei
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Isotactic Polypropylene ◽  
Isothermal Crystallization ◽  
Hyperbranched Polymer ◽  
Crystallization Rate ◽  
Crystallization Activation Energy ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Kinetics Of

In this paper, the isothermal crystallization kinetics of isotactic polypropylene (iPP) and iPP with 5% hyperbranched polymer (HBP) added had been investigated by differential scanning calorimetry (DSC). The results show that a small addition of HBP affects the crystallization behavior of iPP. During isothermal crystallization, the crystallization rate of the blend is higher than those of iPP remarkably. An increase in the Avrami exponent may be attributed to the fractal structure of hyperbranched polymer. The crystallization activation energy is estimated by the Friedman equation, the results show that the activation energy decreases remarkably by addition of HBP and the crystallization rate of the blend is more sensitive to temperature than that of iPP.

Crystallization Kinetics in Cu64.5Zr35.5 Binary Metallic Glass

2017 ◽  
Vol 727 ◽  
pp. 233-238 ◽  
Author(s):  
Qian Gao ◽  
Zeng Yun Jian ◽  
Jun Feng Xu ◽  
Man Zhu
Keyword(s):  
Activation Energy ◽  
Grain Growth ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
Crystallization Kinetic ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Growth Activation ◽  
Local Activation Energy ◽  
Kinetics Of

The crystallization kinetics of melt-spun Cu64.5Zr35.5 amorphous alloy ribbons was investigated using differential scanning calorimetry (DSC) at different heating rates. Besides, the Kissinger and isoconversional approaches were used to obtain the crystallization kinetic parameters. As shown in the results, the activation energies for glass transition and crystallization process at the onset, peak and end crystallization temperatures were obtained by means of Kissinger equation to be 577.65 ± 34, 539.86 ± 54, 518.25 ± 20 and 224.84 ± 2 kJ/mol, respectively. The nucleation activation energy Enucleation is greater than grain growth activation energy Egrowth, indicating that the nucleation process is harder than grain growth. The local activation energy Eα decreases in the whole crystallization process, which suggests that crystallization process is increasingly easy.

scholarly journals Crystallization kinetics of K2O·TiO2·3GeO2 glass studied by DTA

2008 ◽  
Vol 40 (3) ◽  
pp. 333-338 ◽  
Author(s):  
S. Grujic ◽  
N. Blagojevic ◽  
M. Tosic ◽  
V. Zivanovic ◽  
J. Nikolic
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Samples ◽  
Kinetics Of

Crystallization kinetics of K2O?TiO2?3GeO2 glass was investigated by differential thermal analysis (DTA). Experiments were performed on powder samples with a particle size < 0.037 mm. The glass samples were heated at different rates in the temperature range 20-750?C. The kinetic parameters, activation energy for the crystallization process, Ec and Avrami exponent, n were calculated. Powder X-ray diffraction analysis (XRD) of crystallized glass reveals the presence of crystalline K2O?TiO2?3GeO2 indicating polymorphic crystallization with interface controlled crystal growth.

scholarly journals Effect of cobalt content on non-isothermal crystallization kinetics of Fe-based amorphous alloys

2019 ◽  
pp. 44-52
Author(s):  
Carolina Parra-Velásquez ◽  
Darling Perea-Cabarcas ◽  
Francisco Javier Bolivar-Osorio
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Melt Spinning ◽  
Cobalt Content ◽  
Amorphous Structure ◽  
Scanning Calorimetry ◽  
Jma Model ◽  
Nucleation Mechanisms ◽  
Local Activation Energy ◽  
Kinetics Of

In the present study, FeSiBP and FeCoSiBP ribbons with a fully amorphous structure were made by melt spinning technique. A detailed analysis of the isochronal crystallization behavior is presented in this paper. The influence of cobalt on the crystallization kinetics of the alloys was studied under isochronal conditions using differential scanning calorimetry (DSC). Apparent and local activation energy values were determined by Kissinger, Ozawa and Kissinger-Akahira-Sunose (KAS) methods. The results indicate that appropriate amounts of cobalt can significantly enhance the thermal stability of Fe-based alloys, through an increase in nucleation activation energy from 538kJ/mol to 701kJ/mol, obtained by Kissinger method. Furthermore, with the method proposed by Matusita, it was possible to obtain global values for the Avrami exponent, noting that from a general perspective, Co changes the mechanism from diffusion controlled to interface controlled. This leads to the conclusion that the crystallization process is complex and takes place in more than one stage. Therefore, the determination of nucleation mechanisms and dimensional growth is difficult due to the inapplicability of the Johnson-Melh-Avrami (JMA) model. As such, a study under isothermal conditions is suggested, in order to achieve a full understanding of the mechanisms involved.

Miscibility and crystallization kinetics of poly(ε- caprolactone)/bezoxazine blends

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Hsiu-Jung Chiu ◽  
Ruey-Shi Tsai ◽  
Jieh-Ming Huang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Crystallization Kinetics ◽  
Equilibrium Temperature ◽  
Cooling Process ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Polarized Optical Microscopy ◽  
Equation Analysis ◽  
Kinetics Of

Abstract The miscibility and crystallization kinetics of the blends of poly(e- caprolactone) (PCL) and bezoxazine (B-m) resin was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It was found that PCL/B-m blends were miscible in the melt. Thus the blend exhibited a single glass transition temperature (Tg), which increased with increasing B-m composition and the crystal equilibrium temperature (Tmo) depressed with the addition of B-m from the Hoffman-Weeks equation analysis. The freezing crystallization temperature (Tfc) for the nonisothermal crystallization on the cooling process, and the spherulitic growth and overall crystallization rates of PCL for the isothermal crystallization were depressed with the addition of B-m component, attributing it to the dilution of PCL concentration due to the addition of B-m.

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