The different initial oxidation kinetics of Zr(0001) and Zr(101−0) surfaces

2011 ◽  
Vol 110 (2) ◽  
pp. 024904 ◽  
Author(s):  
Georgijs Bakradze ◽  
Lars P. H. Jeurgens ◽  
Eric J. Mittemeijer
Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2816 ◽  
Author(s):  
Yuanlin Li ◽  
Xiongmin Liu ◽  
Qiang Zhang ◽  
Bo Wang ◽  
Chang Yu ◽  
...  

A self-designed reaction device was used as a promising equipment to investigate the oxidation characteristics and kinetics of rosin pentaerythritol ester (RPE) under UV irradiation. Photo-oxidation kinetics and the initial quantum yield (Φ) of RPE were calculated. The initial oxidation product of the photo-oxidation reaction—peroxide was analyzed by iodimetry. The peroxide concentration is related to the light intensity (I) and the temperature (T), and the increasing T and I would destabilize the RPE by accelerating peroxide forming. Photo-oxidation of RPE follows the pseudo first-order reaction kinetics. The relationship between activation energy and logarithm of light intensity (ln I) is linear, and it is expressed as Ea = −4.937ln I + 45.565. Φ was calculated by the photo-oxidation kinetics, and the average value of Φ was 7.19% in the light intensity range of 200–800 μW cm−2. This research can provide fundamental information for application of RPE, and help obtain a better understanding of the stability of rosin esters.


2021 ◽  
Vol 21 (3) ◽  
pp. 2067-2070
Author(s):  
Chul-Hong Bae ◽  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
...  

In this study, the effects of constituent phases on the oxidation kinetics of an Al-7 mass%Mg alloy containing a trace of Ca were investigated. A Mg+Al2Ca master alloy was used to add Mg and Ca simultaneously. Scheil-Gulliver cooling by thermodynamic calculation showed that the addition of Ca led to the formation of Ca-based intermetallic compounds, such as Al4Ca and Laves C36, after solidification. Based on weight increase indicated by the oxidation test and surface analysis, it was found that the presence of Ca-based phases significantly improved the oxidation resistance and slowed down the oxidation rates. Based on the review of phase diagrams with oxygen partial pressure by thermodynamic calculation, it was thought that in the initial oxidation, MgO and MgAl2O4 were formed on the surfaces of the Al–Mg alloys, leading to further oxidation. The Ca-based intermetallic compounds formed Ca–Mg–Al based oxides, which possibly contributed to the formation of a relatively dense oxide layer.


2020 ◽  
Vol 697 ◽  
pp. 121600
Author(s):  
S. Ohno ◽  
K. Tanaka ◽  
H. Kodama ◽  
M. Tanaka ◽  
A. Yoshigoe ◽  
...  

2010 ◽  
Vol 8 (S1) ◽  
pp. 87-90 ◽  
Author(s):  
Shigeng Song Shigeng Song ◽  
Frank Placido Frank Placido

2011 ◽  
Vol 675-677 ◽  
pp. 209-212 ◽  
Author(s):  
Dong Ya Huang ◽  
Bin Wang ◽  
Vincent Ji ◽  
Tao Zhang

The isothermal initial oxidation kinetics of Zr55Cu30Al10Ni5 bulk metallic glass in glassy state (lower than Tg = 685K) and in surpercooled liquid state (Tg = 685 K < T < Tx=774 K) is investigated under dry air by thermogravimetric method in short-term stage (for 1.5 hours). A protective parabolic law is followed in glassy state, except at 573 K where a linear law is followed. The self-limiting oxidation kinetics evolves from a short linear stage to a steady mild growth stage in supercooled liquid state at 723 K, which is induced mainly by crystallization and by the fast growth of dense scale. The growth of the scale is dominated by the formation of tetragonal-ZrO2 (t- ZrO2) in the range of 623 K - 673 K in glassy state for 1.5 hours. The activation energy of oxidation is mainly piloted by the diffusion of oxygen ions.


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