The Influence of Chrome in the Oxidation Process of Steels in Flowing LBE

2009 ◽  
Author(s):  
Taide Tan ◽  
Yitung Chen
Keyword(s):  
Oxidation Process ◽  
Alloying Element ◽  
Mesoscopic Scale ◽  
Protective Oxide ◽  
Scale Removal ◽  
Chrome Oxide ◽  
Protective Oxide Film ◽  
Oxidation Model ◽  
Stochastic Cellular Automaton

The role of the alloying element has been analyzed during the oxidation process of stainless steels in the flowing lead bismuth eutectic (LBE) environment. The growth of the protective oxide film of steels has been studied at a mesoscopic scale. The influence of chrome has been studied using the developed stochastic cellular automaton mesoscopic oxidation model, considering the formation of the chrome oxide and magnetite. During the oxidation process, the scale removal effect has been taken into account as well.

Formation and Protection of Fe-Cr Oxide Spinel During the Oxidation Process of Stainless Steels in LBE Environment

2009 ◽  
Author(s):  
Taide Tan ◽  
Yitung Chen
Keyword(s):  
Spinel Layer ◽  
Scale Removal ◽  
Chrome Oxide ◽  
Complex Process ◽  
Oxide Spinel ◽  
Mesoscopic Level ◽  
Cellular Automaton Method ◽  
Stochastic Cellular Automaton ◽  
Nuclear Coolant

The formation of the spinel of magnetite and chrome oxide, is a very complex process, especially with the scale removal effect in flowing lead bismuth eutectic (LBE) nuclear coolant. This paper studied the formation and the protection of the spinel of magnetite and chrome oxide on stainless steel, in different environments at a mesoscopic level. The role of the alloying element has been analyzed. The formation of the spinel of magnetite and chrome oxide and the scale removal effect are simulated using a stochastic cellular automaton method. The protection of this spinel layer to the structural materials has been analyzed.

Oxidation Effect on Welded AA6061 Al Alloy Using ER4043 Filler Metal

2011 ◽  
Vol 66-68 ◽  
pp. 46-49
Author(s):  
Che Lah Nur Azida ◽  
Azman Jalar ◽  
Norinsan Kamil Othman ◽  
Abdul Razak Daud
Keyword(s):  
Total Pressure ◽  
Oxidation Process ◽  
Filler Metal ◽  
Al Alloy ◽  
Parent Metal ◽  
Alloying Element ◽  
Oxide Formation ◽  
Oxide Morphology ◽  
Protective Oxide ◽  
Oxidation Effect

As-welded AA6061 Al alloy using Al-Si-Mg (ER 4043) filler metal was subjected to oxidationexposure in flowing air gas for 40hrs at 600oC at a total pressure of approximately 1 atm. SEM andEDAX were chosen to characterize the morphology microstructure of oxide formation on welded jointafter oxidation process. Different oxide morphology were found on parent and fusion metal due to thedifferences of the alloying element. The morphology of the oxide shows the protection oxide surfacewere developed on parent metal while non-protective oxide formed on fusion metal.

The Role of H2O2 and K2S2O8 as Oxidizing Agents for Accelerated Corrosion Testing

CORROSION ◽  
10.5006/3443 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 373-384
Author(s):  
Mary E. Parker ◽  
Russell Repasky ◽  
Srishti Shrivastava ◽  
Robert G. Kelly
Keyword(s):  
Immersion Test ◽  
Corrosion Testing ◽  
Solution Ph ◽  
Protective Oxide ◽  
Accelerated Corrosion ◽  
Oxidizing Agents ◽  
Accelerated Corrosion Testing ◽  
Protective Oxide Film ◽  
Kinetics Of

In this work, the application of hydrogen peroxide (H2O2) and potassium persulfate (K2S2O8) in accelerated corrosion testing was considered. H2O2 is already used as an accelerant in the standard immersion test ASTM G110, and K2S2O8 is an oxidizing agent that shows promise for corrosion testing applications. A Koutecky-Levich approach was used to investigate the cathodic kinetics of both oxidizing agents as well as dissolved oxygen (O2). Cathodic kinetics for O2, H2O2, and S2O82− were faster when measured on a platinum electrode than when measured on an AA2060-T3 electrode. This difference was attributed to the additional limit to cathodic kinetics posed by the protective oxide film on aluminum. H2O2 was a more potent accelerant than K2S2O8 at a concentration of 0.1 M due to the faster cathodic kinetics of H2O2 on aluminum. However, K2S2O8 was more convenient to use in a laboratory setting due to its stability during storage. The severity of tests using K2S2O8 was increased by lowering the solution pH to 2.28. At the low solution pH, cathodic kinetics and extent of attack increased.

Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

1970 ◽  
Vol 28 ◽  
pp. 510-511
Author(s):  
L. P. Lemaire ◽  
D. E. Fornwalt ◽  
F. S. Pettit ◽  
B. H. Kear
Keyword(s):  
Oxide Scale ◽  
Oxidation Process ◽  
Short Circuit ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Thin Oxide Films ◽  
Diffusion Paths ◽  
Oxidation Resistant ◽  
Structural Imperfections ◽  
Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

scholarly journals Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1043
Author(s):  
Vitor Bonamigo Moreira ◽  
Anna Puiggalí-Jou ◽  
Emilio Jiménez-Piqué ◽  
Carlos Alemán ◽  
Alvaro Meneguzzi ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Active Sites ◽  
Modified Electrodes ◽  
Chemical Conversion ◽  
Ceramic Materials ◽  
Point Of View ◽  
Oxide Coatings ◽  
Alloying Element ◽  
Substrate Nature

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

scholarly journals Dynamics of Oxidation of Reduced Forms of CO2 under Electrochemical and Open-Сircuit Conditions on Polycrystalline Pt in H2CO3

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 274
Author(s):  
Alexander V. Smolin ◽  
Мikhail N. Mikhailov ◽  
Aleksey F. Gadzaov ◽  
Leonid M. Kustov
Keyword(s):  
Quantum Chemical ◽  
Preliminary Analysis ◽  
Oxidation Reaction ◽  
Density Functional ◽  
Oxidation Process ◽  
Open Circuit ◽  
Organic Substances ◽  
Oxidation Of Co ◽  
Reduced Forms

The problem of identifying correlations between catalytic and electrocatalytic processes is one of the fundamental problems of catalysis among “simple” organic substances, and the oxidation of CO and rCO2 is of great interest, since CO and CO2 are considered in pairs both during catalytic and electrocatalytic transformations. In the case of electrocatalysis, this analysis is important in the study of fuel cells. In this paper, we studied the correlation between the oxidation of reduced forms of CO2 (rCO2) under potentiodynamic-galvanoctatic electrochemical and open-circuit conditions of measurements on polycrystalline (pc)Pt in H2CO3. Periodic oscillations are revealed at the oxidation of Had and rCO2 on (pc)Pt. Quantum chemical calculations were carried out on the Pt13 cluster in order to identify the mechanisms of the rCO2 oxidation reaction. The correspondence in the energy parameters of the oxidation process of rCO2 under open-circuit conditions and electrochemical conditions is shown. The preliminary analysis of the system using density functional (DFT) calculations is carried out and the most stable systems that are based on Pt13 are found, namely rOH-Pt13-(CO)n, rOH-Pt13-(COH) and rOH-Pt13-(rCOOH). OH• species was chosen as the most likely candidate for the role of the oxidant for rCO2. Preliminary calculations for the expected reactions were carried out, and the optimal PES is revealed.

scholarly journals The simultaneous removal of bisphenol A, manganese and ammonium from groundwater by MeOx: The role of chemical catalytic oxidation for bisphenol A

2021 ◽  
Author(s):  
Yingming Guo ◽  
Ben Ma ◽  
Jianxiong Huang ◽  
Jing Yang ◽  
Ruifeng Zhang
Keyword(s):  
Oxide Film ◽  
Bisphenol A ◽  
Dissolved Oxygen ◽  
Oxidation Process ◽  
Pilot Scale ◽  
Simultaneous Removal ◽  
Chemical Forms ◽  
Synergy Effect ◽  
Iron And Manganese

Abstract The iron and manganese oxide filter film (MeOx) were used to research the simultaneous removal of bisphenol A (BPA), manganese (Mn2+) and ammonium (NH4+) in a pilot-scale filter system. We found that 0.52 mg/L of BPA could be removed while consuming 5.44 mg/L of dissolved oxygen (DO). Since the oxidation process of NH4+ and BPA both consume the DO in water, the presence of NH4+ can hinder the removal of BPA. The presence of Mn2+ in water had a synergy effect on the BPA removal. The filter film was characterized by SEM, XRD and XPS. Some substances were generated to block the pores of the oxide film, and a small amount of film was found to crack and fall off. The elemental composition of C and O were both increased by about 9%, the composition of Mn was decreased from 63.48% to 44.55%, and the reduced manganese substance might affect the activity of the oxide film. The main chemical forms of MeOx are Mn6O12·3H2O, MnFe2O4 or Mn3O4. The decrease in the removal efficiency of BPA was mainly due to the C-containing intermediate [−CH2C − H(OH)]n covering the surface of the oxide film and blocking the pore size of the film.

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