The Temperature Dependence of the Atoms Co Diffusion Coefficient in Pt80Co20(111) Alloy

2007 ◽  
Vol 265 ◽  
pp. 19-23
Author(s):  
M. Vasylyev ◽  
Vitaliy A. Tinkov ◽  
Sergey I. Sidorenko ◽  
S.M. Voloshko
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Temperature Dependence ◽  
Surface Segregation ◽  
Surface Region ◽  
Near Surface ◽  
Kinetics Of

The method of Ionization Spectroscopy is used to study the thermo-induced kinetics of surface segregation of the Pt80Co20(111) alloy components. The temperature dependence of the Co diffusion coefficient in this alloy is determined. It is found that the value of the activation energy for the segregation of Co atoms in the near-surface region is close to the heat of sublimation of pure Co.

scholarly journals Unexpected Role of Electronic Coupling between Host Redox Centers in Transport Kinetics of Lithium Ions in Olivine Phosphate Materials

2021 ◽  
Author(s):  
Yu Gao ◽  
Jun Huang ◽  
Yuwen Liu ◽  
Shengli Chen
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Lithium Ion ◽  
Transport Kinetics ◽  
Electronic Coupling ◽  
Lithium Ions ◽  
Kinetics Of ◽  
Olivine Phosphate ◽  
Redox Centers

The discrepancy between the trend in the diffusion coefficient of lithium ion (DLi+) and that in the activation energy of ion hopping signals hidden factors determining ion transport kinetics in...

scholarly journals Drying Kinetics of Noni Seeds

2019 ◽  
Vol 11 (5) ◽  
pp. 250 ◽  
Author(s):  
Wellytton Darci Quequeto ◽  
Osvaldo Resende ◽  
Patrícia Cardoso Silva ◽  
Fábio Adriano Santos e Silva ◽  
Lígia Campos de Moura Silva
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Moisture Content ◽  
Mathematical Models ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Information Criterion ◽  
Drying Kinetics ◽  
Kinetics Of

Noni seeds have been used for years as an important medicinal source, with wide use in the pharmaceutical and food industry. Drying is a fundamental process in the post-harvest stages, where it enables the safe storage of the product. Therefore, the present study aimed to fit different mathematical models to experimental data of drying kinetics of noni seeds, determine the effective diffusion coefficient and obtain the activation energy for the process during drying under different conditions of air temperature. The experiment used noni seeds with initial moisture content of 0.46 (decimal, d.b.) and dehydrated up to equilibrium moisture content. Drying was conducted under different controlled conditions of temperature, 40; 50; 60; 70 and 80 ºC and relative humidity, 24.4; 16.0; 9.9; 5.7 and 3.3%, respectively. Eleven mathematical models were fitted to the experimental data. The parameters to evaluate the fitting of the mathematical models were mean relative error (P), mean estimated error (SE), coefficient of determination (R2), Chi-square test (c2), Akaike Information Criterion (AIC) and Schwarz’s Bayesian Information Criterion (BIC). Considering the fitting criteria, the model Two Terms was selected to describe the drying kinetics of noni seeds. Effective diffusion coefficient ranged from 8.70 to 23.71 × 10-10 m2 s-1 and its relationship with drying temperature can be described by the Arrhenius equation. The activation energy for noni seeds drying was 24.20 kJ mol-1 for the studied temperature range.

Effect of Microstructure on the Dissolution Kinetics of Copper Thin Films in Dilute Aqueous Solutions of Cupric Chloride

1993 ◽  
Vol 323 ◽  
Author(s):  
L. Harper Walsh ◽  
N. B. Feilchenfeld ◽  
J. A. Schwarz
Keyword(s):  
Grain Size ◽  
Grain Orientation ◽  
Dissolution Kinetics ◽  
Surface Region ◽  
Practical Method ◽  
Reaction Rates ◽  
Near Surface ◽  
Dilute Aqueous Solutions ◽  
Microelectronics Industry ◽  
Kinetics Of

ABSTRACTMicrostructural differences in copper deposited by four techniques commonly used in the microelectronics industry were previously reported. [1] The reaction rates were predicted using either grain size or grain orientation as the dominant microstructure characteristic. A practical method to monitor copper speciation was developed.[2] This technique was used to measure the reaction rates for the different copper films under two different etching conditions. The results are explained using grain size, grain orientation and near surface region composition.

scholarly journals Транспортные процессы с участием атомов углерода между поверхностью и объемом родия при образовании и разрушении графена

2020 ◽  
Vol 54 (6) ◽  
pp. 552
Author(s):  
Е.В. Рутьков ◽  
Е.Ю. Афанасьева ◽  
Н.Р. Галль
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Temperature Dependence ◽  
Atomic Carbon ◽  
Graphene Growth ◽  
Carbon Dissolution ◽  
The Difference ◽  
Kinetics Of

Equilibrium transport of atomic carbon between Rh surface and bulk has been studied. This transport controls the kinetics of the phase transition resulting in graphene growth or destruction. The difference ΔE=0.7 eV has been measured between the activation energy of atomic carbon dissolution E1s and that of its segregation from the bulk to the surface E1s. The temperature dependence of chemisorbed carbon critical cover Neq = Neq(T) has been measured, that is the cover when 2D phase transition takes place and graphene islands start to grow. E.g., Neq = 7.7•1014 cm-2 at T = 1800 K, and Neq = 3.1•1014 cm-2 at T = 1000 K.

scholarly journals Effect of Surface Roughness on Oxidation Resistance of Stainless Steel AISI 316Ti During Exposure at High Temperature

2020 ◽  
Vol 29 (12) ◽  
pp. 8060-8069
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Oxidation Resistance ◽  
Surface Preparation ◽  
Surface Region ◽  
Lower Surface ◽  
Near Surface ◽  
Steel Aisi ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractIn the present work, the influence of surface roughness on oxidation kinetics of AISI 316Ti stainless steel and its consequences in term of oxidation resistance were investigated. Namely, the effect of surface roughness on oxidation resistance was evaluated during different types of cyclic oxidation tests at 900 and 1000 °C. The obtained results revealed that alloy possessing higher surface roughness showed longer lifetime compared to that with lower surface roughness. It was also found that more severe cyclic conditions suppressed the positive effect of surface roughness on sample’s lifetime. The better oxidation resistance of rougher alloy was correlated with suppressed formation of Fe-rich nodules on ground surfaces and explained by the combined effect of introduced defects in the near-surface region and possible increase in residual stresses caused by mechanical surface preparation.

Temperature dependence of hydrogen depth distribution in the near-surface region of stainless steel

Vacuum ◽  
2014 ◽  
Vol 109 ◽  
pp. 230-233 ◽  
Author(s):  
Kotaro Takeyasu ◽  
Masuaki Matsumoto ◽  
Katsuyuki Fukutani
Keyword(s):  
Stainless Steel ◽  
Temperature Dependence ◽  
Depth Distribution ◽  
Surface Region ◽  
Near Surface

Effect of Molecular Weight, Shape of the Molecule, and Presence of Polar Groups on the Autohesion of High Polymers. III

1957 ◽  
Vol 30 (2) ◽  
pp. 548-554 ◽  
Author(s):  
S. S. Voyutskiĭ ◽  
B. V. Shtarkh
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Temperature Dependence ◽  
Structural Changes ◽  
Chain Molecule ◽  
Complete Disappearance ◽  
Short Side ◽  
Polar Groups ◽  
Kinetics Of ◽  
High Polymers

Abstract 1. It is shown for polyisobutylenes of different molecular weight that increase in the size of the chain molecule retards autohesion, but increases the limiting value to which the work of autohesion tends with increasing contact time. 2. Investigation of the temperature dependence of autohesion of polyisobutylenes showed that the activation energy does not depend on the molecular weight of the polyisobutylene. 3. It is shown for polybutadienes with varying contents of 1,4- and 1,2-structures that autohesion decreases with increase in the number of short side groups in the molecule, which apparently hinder diffusion by purely steric causes. 4. Investigation of the temperature dependence of autohesion of butadienenitrile copolymers with different contents of acrylonitrile in the molecule showed that the activation energy of autohesion increases with increase of polar nitrile groups in the polymer. 5. It is shown for the vulcanization of natural rubber that the formation of a spatial structure results in complete disappearance of autohesion in high polymers. It is shown that the kinetics of changes of autohesion during vulcanization can effectively characterize the structural changes which take place in the polymer during the process.

About Fe Diffusion in Cu

2012 ◽  
Vol 323-325 ◽  
pp. 171-176 ◽  
Author(s):  
D. Prokoshkina ◽  
A.O. Rodin ◽  
V. Esin
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Temperature Dependence ◽  
Boundary Diffusion ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Radiotracer Technique ◽  
Exponential Factor ◽  
Temperature Range

The temperature dependence of the bulk diffusion coefficient of Fe in Cu is determined by EDX in the temperature range from 923 to 1273 K, , m2/s. These results are different from that obtained earlier by radiotracer technique: activation energy is less by 30 kJ/mol and pre-exponential factor is 50 times smaller. Deviations from ideality of investigated solutions do not explain the differences; consequently, the thermodynamical factor would not responsible for such an effect. Fast grain boundary diffusion of Fe in Cu was not observed in the temperature range from 823 to 1073 K.

In Situ Tem Studies of The Growth of Strained Si1-xGex By Solid Phase Epitaxy

1990 ◽  
Vol 202 ◽  
Author(s):  
D. C. Paine ◽  
D. J. Howard ◽  
N. D. Evans ◽  
D. W. Greve ◽  
M. Racanelli ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Surface Region ◽  
In Situ Tem ◽  
Solid Phase Epitaxy ◽  
Near Surface ◽  
Strained Layer ◽  
Epitaxial Regrowth

ABSTRACTIn this paper we report on the epitaxial growth of strained thin film Si1-xGex on Si by solid phase epitaxy. For these solid phase epitaxy experiments, a 180-nm-thick strained-layer of Si1-xGex with xGe=11.6 at. % was epitaxially grown on <001> Si using chemical vapor deposition. The near surface region of the substrate, including the entire Si1-xGex film, was then amorphized to a depth of 380 nm using a two step process of 100 keV, followed by 200 keV, 29Si ion implantation. The epitaxial regrowth of the alloy was studied with in situ TEM heating techniques which enabled an evaluation of the activation energy for strained solid phase epitaxial regrowth. We report that the activation energy for Si1-xGex (x=l 1.6 at. %) strained-layer regrowth is 3.2 eV while that for unstrained regrowth of pure Si is 2.68 eV and that regrowth in the alloy is slower than in pure Si over the temperature range 490 to 600°C.

Diffusion of 57Co in amorphous Fe–RE (RE = Dy, Tb, and Ce) and Fe–Si–B alloys

1993 ◽  
Vol 8 (9) ◽  
pp. 2231-2238 ◽  
Author(s):  
Kazumasa Yamada ◽  
Yoshiaki Iijima ◽  
Kazuaki Fukamichi
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Temperature Dependence ◽  
Tracer Diffusion ◽  
Atomic Size ◽  
Exponential Factor ◽  
Dc Sputtering ◽  
The Matrix ◽  
Diffusion Temperature ◽  
Order Of Magnitude

Tracer diffusion of 57Co in amorphous Fe100−xDyx (x = 20–40), Fe75Tb25, Fe67Ce33, and Fe80Si6B14 alloys prepared by dc sputtering has been studied at temperatures of 523 and 573 K. In the Fe–Dy alloys the diffusion coefficient of 57Co shows a maximum at 33 at.% Dy. The magnitude of the diffusion coefficient of 57Co in Fe75Tb25 is nearly equal to that in Fe75Dy25, while those in Fe67Ce33 and Fe80Si6B14 are about one order of magnitude less than the values in Fe67Dy33 and Fe80Dy20. This suggests that the atomic size of the diffusant and the density of the matrix are dominant in the diffusion. Temperature dependence of the diffusion coefficient D of 57Co in the amorphous Fe75Dy25 alloy has been determined in the range from 493–673 K. It shows a linear Arrhenius relationship expressed by D = 5.7 × 10−2 exp(−199 kJ mol−1/RT) m2 s−1. The magnitudes of the pre-exponential factor and the activation energy suggest that the cobalt tracer atoms in the amorphous Fe75Dy25 alloy diffuse by an interstitial-like mechanism.

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