Activation Energy of Crystallization for Trihydroxystearin, Stearic Acid, and 12-Hydroxystearic Acid under Nonisothermal Cooling Conditions

2011 ◽  
Vol 11 (8) ◽  
pp. 3593-3599 ◽  
Author(s):  
Ricky Sze Ho Lam ◽  
Michael A. Rogers
Keyword(s):  
Activation Energy ◽  
Stearic Acid ◽  
Hydroxystearic Acid ◽  
Cooling Conditions ◽  
Activation Energy Of Crystallization

The activation energy of crystallization of amorphous Fe40Ni40P14B6

1982 ◽  
Vol 28 (2) ◽  
pp. 137-144 ◽  
Author(s):  
W. Fernengel ◽  
H. Kronm�ller ◽  
M. Rapp ◽  
Y. He
Keyword(s):  
Activation Energy ◽  
Activation Energy Of Crystallization

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.

About Thermostability of Fe-Ni-P Amorphous Alloys

2012 ◽  
Vol 188 ◽  
pp. 21-26
Author(s):  
Aurel Raduta ◽  
Mircea Nicoară ◽  
Cosmin Locovei
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Amorphous Alloys ◽  
Structural Changes ◽  
P System ◽  
X Rays ◽  
Heating Rates ◽  
Planar Flow Casting ◽  
Activation Energy Of Crystallization

A research program has been completed in order to analyze structural changes during heating of amorphous alloys belonging to Fe-Ni-P system. Special attention has been given to thermodynamics and mechanism of crystallization, to determine some aspects of development for crystalline phases. Experimental material used to determine characteristics of crystallization consisted in long ribbons, 30 thick and 18 mm wide, fabricated by mean of “Planar Flow casting” as amorphous Fe42Ni38P16B4alloy. Differential Thermal Analysis (DTA) and X-rays diffraction have been used to determine crystallization temperature of this alloy. Curves of differential thermal analysis for heating rates ranging between 1°C/minute and 20 °C/minute have been used to determine activation energy of crystallization.

Application of DSC Technique in Study of Glass Ceramic

2010 ◽  
Vol 105-106 ◽  
pp. 743-745
Author(s):  
Li Jie Qu ◽  
Bin Li ◽  
Jing Wang ◽  
Yue Mei Gu
Keyword(s):  
Activation Energy ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Differential Scanning Calorimetric ◽  
Isothermal Method ◽  
Practical Applications ◽  
Activation Energy Of Crystallization ◽  
Optimum Heat ◽  
The Stability

Glass-ceramics with desired microstructures and properties are controlled by nucleation and crystallization. The nucleation and crystallization of glass, which include the nucleation, crystal growth rates and the activation energy, are important in understanding the stability of glass in practical applications. The activation energy of crystallization (E) plays an important role in determining the utility of glass ceramic. The amorphous to crystalline transformation in glass can be investigated by isothermal and non-isothermal method which is differential scanning calorimetric (DSC). In the isothermal method, the sample is measured as a function of time, while in the non-isothermal method the sample is recorded as a function of temperature. An advantage of the non-isothermal method is the possibility of reaching a test temperature instantaneously and during the time, which system needs to stabilize. However, the isothermal method does not have this advantage. In the present work, this technique was used to calculate the activation energy of CaO-Al2O3-SiO2-CeO2 glass-ceramics. DSC technique can be used as to determine the optimum heat treatment temperature. The advantage of the DSC technique in study of glass-ceramics is that it requires much less time.

Ti50Fe25Ni25 Amorphous Alloy Prepared by Mechanical Alloying

2011 ◽  
Vol 327 ◽  
pp. 76-80
Author(s):  
Yu Ying Zhu ◽  
Qiang Li ◽  
Yun Hua He ◽  
Ge Wang ◽  
Xing Hua Wang
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Mechanical Alloying ◽  
High Energy ◽  
Structural Features ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Crystallization Peak ◽  
Activation Energy Of Crystallization ◽  
Amorphous Alloy Powder

A new ternary Ti-based amorphous alloy, Ti50Fe25Ni25, is prepared by the mechanical alloying. The milling is performed in a high-energy planetary ball mill under argon atmosphere. Fully Ti50Fe25Ni25amorphous alloy powder is obtained after milled 160h. The milling speed is 300rpm and the weighs ratio of ball to powder is 10:1. The structural features are studied by X-ray diffraction and field emission scanning electron microscope, and the thermal stability is investigated by a differential scanning calorimeter. The super-cooled liquid region of the amorphous alloy increases from 98K to 119K as the heating rate increasing from 10K/min to 40K/min. The effective activation energy of crystallization is estimated with modified Kissinger’s plot. The initial crystallization activation energyEx1and the first crystallization peakEp1are 155.9KJ/mol and 188.5KJ/mol, respectively.

scholarly journals Devitrification of Zr55Cu30Al15Ni5Bulk Metallic Glass under Heating and HPT Deformation

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1329 ◽  
Author(s):  
Galina Abrosimova ◽  
Boris Gnesin ◽  
Dmitry Gunderov ◽  
Alexandra Drozdenko ◽  
Danila Matveev ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Metallic Glass ◽  
Metastable Phase ◽  
Hexagonal Structure ◽  
Crystalline Phases ◽  
Space Group ◽  
Activation Energy Of Crystallization ◽  
Nanocrystal Formation ◽  
Crystallization Stage

The nanocrystal formation in Zr55Cu30Al15Ni5 bulk metallic glass was studied under heat treatment and deformation. The activation energy of crystallization under heating is 278 kJ/mol. Different crystalline phases were found to be formed during crystallization under heating and deformation. At the first crystallization stage, the metastable phase with a hexagonal structure (lattice of space group P63/mmc with the parameters a = 8.66 Å, c = 14.99 Å) is formed under heat treatment. When the temperature rises, the metastable phase decays with the formation of stable crystalline phases. The crystalline Zr2Cu phase with the lattice of space group Fd3m is formed during crystallization under the action of deformation. It was determined that during deformation nanocrystals are formed primarily in the subsurface regions of the samples.

The thermal stability and activation energy of crystallization of (Cu61.8Zr38.2)1−xAlx bulk metallic glasses

2007 ◽  
Vol 353 (32-40) ◽  
pp. 3421-3424 ◽  
Author(s):  
Qing Wang ◽  
Jianbing Qiang ◽  
Yingmin Wang ◽  
Junhai Xia ◽  
Huogen Huang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Activation Energy Of Crystallization

Au0.80Cu0.10Y0.10, A Gold-Rich Ternary Alloy Glass with Tc > 400°C and its Crystallization Kinetics

1993 ◽  
Vol 321 ◽  
Author(s):  
Sunil V. Gokhale ◽  
Krassimir G. Marchev ◽  
Welville B. Nowak ◽  
Bill C. Giessen
Keyword(s):  
Activation Energy ◽  
Rare Earth ◽  
Room Temperature ◽  
Glassy State ◽  
Rapid Solidification Processing ◽  
Arc Furnace ◽  
Solidification Processing ◽  
Glass Forming ◽  
New Family ◽  
Activation Energy Of Crystallization

ABSTRACTThere are no reported gold-rich alloys that are both readily glass forming (RGF) upon rapid solidification processing (RSP) and, in the glassy state, have crystallization temperatures Tc sufficiently high to insure long metastable life times at room temperature. A representative of a new family of ternary gold-based glasses is described that contain Cu and a rare earth (RE) Metal (or Y), with total addition element concentrations as low as 15 at. pet., and its crystallization characteristics are reported. Under RSP processing by arc furnace hammer-and-anvil quenching, the alloy Au0.80Cu0.10Y0.10 readily forms a ductile glass, with Tc = 685 K, ΔHc = 1.25 kJ/g-Mole and an activation energy of crystallization ΔE3 (cryst.) = 190 kJ/g-Mole.

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