Effects of Constituent Phases on Oxidation Kinetics of Al–Mg Alloys Containing a Trace of Ca

2021 ◽  
Vol 21 (3) ◽  
pp. 2067-2070
Author(s):  
Chul-Hong Bae ◽  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Intermetallic Compounds ◽  
Master Alloy ◽  
Oxidation Kinetics ◽  
Thermodynamic Calculation ◽  
Mg Alloys ◽  
Initial Oxidation ◽  
Oxidation Rates ◽  
Kinetics Of ◽  
Al Mg Alloys

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.

Oxidation Kinetics of Steels Utilized in the Production of Valves in Automobile Industry

2012 ◽  
Vol 31 (6) ◽  
pp. 775-779 ◽  
Author(s):  
Z. Grzesik ◽  
Z. Jurasz ◽  
K. Adamaszek ◽  
S. Mrowec
Keyword(s):  
Phase Composition ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxidation Resistance ◽  
Automobile Industry ◽  
Oxidation Kinetics ◽  
Chromium Content ◽  
Chromium Concentration ◽  
Oxidation Rates ◽  
Kinetics Of

AbstractThe oxidation kinetics of four Fe-Cr-Mn-Ni based steels, utilized in automobile industry, have been studied as a function of temperature (973–1273 K) and oxygen partial pressure (5–105 Pa). It has been shown that the rate of corrosion of these steels under isothermal conditions is determined by diffusion of reagents through the scale, which phase composition and morphology depend first of all on chromium and to some extend also on nickel and manganese contents. The highest oxidation resistance at high temperatures is observed in the case of the X33CrNiMn23-8 steel, containing highest chromium concentration, equal 23.4 wt.% and nickel equal 7.8 wt.%. The remaining three steels with virtually the same chromium content (≈20 wt.%), but lower than that in the first one, show comparable oxidation resistance. Small differences in the oxidation rates of these three steels may be related to different nickel and manganese contents. It has been found also that the rate of corrosion of all steels under investigation does not depend under steady state conditions on oxygen partial pressure.

scholarly journals Characteristics and Kinetics of Rosin Pentaerythritol Ester via Oxidation Process under Ultraviolet Irradiation

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2816 ◽  
Author(s):  
Yuanlin Li ◽  
Xiongmin Liu ◽  
Qiang Zhang ◽  
Bo Wang ◽  
Chang Yu ◽  
...  
Keyword(s):  
Light Intensity ◽  
Oxidation Kinetics ◽  
Pseudo First Order Reaction ◽  
Initial Oxidation ◽  
Photo Oxidation ◽  
Average Value ◽  
Pentaerythritol Ester ◽  
Fundamental Information ◽  
The Stability ◽  
Kinetics Of

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.

Oxidation of PECVD SiC Deposited from Trimethylsilane

1998 ◽  
Vol 555 ◽  
Author(s):  
Peter A. DiFonzo ◽  
Mona Massuda ◽  
James T. Kelliher
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Oxidation Kinetics ◽  
Stoichiometric Composition ◽  
Chemical Vapor ◽  
Oxidation Rates ◽  
Chemical Vapor Deposited ◽  
Kinetics Of ◽  
Sic Films ◽  
Deposition Conditions

AbstractThe stoichiometric composition and oxidation rates ( wet or dry ) of plasma enhanced chemical vapor deposited (PECVD) silicon carbide (SiC) films are effected by the deposition conditions of trimethylsilane (3MS) and carrier gas. We report the oxidation kinetics of SiC thin films deposited in a modified commercial PECVD reactor. A standard horizontal atmospheric furnace in the temperature range of 925–1100°C was used in the oxidation. Oxidized films were measured optically by commercially available interferometer and ellipsometer tools in addition to mechanically using a commercially available profilometer. Activation energies of the parabolic rates were in the range of 20.93 to 335.26 kJ/mol.

scholarly journals Diffusion and Formation of Intermetallic Compounds during Accumulative Roll-Bonding of Al/Mg Alloys

2007 ◽  
Vol 48 (10) ◽  
pp. 2595-2598 ◽  
Author(s):  
Ming-Che Chen ◽  
Che-Wei Kuo ◽  
Chia-Ming Chang ◽  
Chih-Chun Hsieh ◽  
Yin-Yu Chang ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Accumulative Roll Bonding ◽  
Mg Alloys ◽  
Roll Bonding ◽  
Al Mg Alloys

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
Keyword(s):  
Oxidation Kinetics ◽  
Initial Oxidation ◽  
Kinetics Of

Analysis of the Enhanced Growth Rate of Silicon-Oxide Layers in the Thin Regime by Incremental Growth

1992 ◽  
Vol 280 ◽  
Author(s):  
Sergio A. Ajuria ◽  
Prashant U. Kenkare ◽  
Anh Nghiem
Keyword(s):  
Growth Rate ◽  
Oxidation Kinetics ◽  
Silicon Oxide ◽  
Layer Formation ◽  
Silicon Oxidation ◽  
Initial Oxidation ◽  
Initial Layer ◽  
Oxidation Rates ◽  
Incremental Growth ◽  
Unique Method

ABSTRACTSilicon oxidation kinetics in the thin regime are studied by a unique method in which thermally grown as well as densified CVD-deposited oxides are incrementally reoxidized and measured. Strikingly higher oxidation rates are obtained through deposited oxides, as compared to thermal oxides, suggesting that oxidations are suppressed after an initial layer is grown rather than enhanced during initial layer formation. We show that these findings tend to support initial oxidation models based on stress.

A Novel Apparatus to Determine the Bio-Oxidation Kinetics of Sessile Leptospirillum ferriphilum

2013 ◽  
Vol 825 ◽  
pp. 238-241 ◽  
Author(s):  
Porogo Duku ◽  
Sanet H. Minnaar ◽  
Susan T.L. Harrison ◽  
Jochen Petersen
Keyword(s):  
Oxidation Kinetics ◽  
Iron Oxidation ◽  
Packed Bed ◽  
Leptospirillum Ferriphilum ◽  
Oxidation Rates ◽  
Cell Counts ◽  
Ferrous Iron Oxidation ◽  
Uptake Rates ◽  
Carbon Utilisation ◽  
Kinetics Of

A novel apparatus was developed to test the ferrous iron oxidation kinetics of Leptospirillum ferriphilum in predominantly sessile culture, by combining a CSTR under wash-out conditions with a packed bed of inert ceramic saddles. Results indicate that a dense culture of sessile bacteria is established rapidly, which achieves high oxidation rates in all experiments with a yield in terms of CO2 uptake rates comparable or higher to what has been measured in planktonic culture. However, the yield in terms of cell counts changes dramatically, indicating a substantial shift in carbon utilisation in the sessile culture. The apparatus is feasible as a method to study iron oxidation kinetics of sessile cultures, providing it is operated at sufficiently high recycle ratios.

Sign in / Sign up

Export Citation Format

Share Document