A mechanistic model for oxide growth and dissolution during corrosion of Cr-containing alloys

We have developed a corrosion model that can predict metal oxide growth and dissolution rates as a function of time for a range of solution conditions. Our model considers electrochemical reactions at the metal/oxide and oxide/solution interfaces, and the metal cation flux from the metal to the solution phase through a growing oxide layer, and formulates the key processes using classical chemical reaction rate or flux equations. The model imposes mass and charge balance and hence, is labeled as the Mass Charge Balance (MCB) model. Mass and charge balance dictate that at any given time the oxidation (or metal cation) flux must be equal to the sum of the oxide growth flux and the dissolution flux. For each redox reaction leading to the formation of a specific oxide, the metal oxidation flux is formulated using a modified Butler–Volmer equation with an oxide-thickness-dependent effective overpotential. The oxide growth and dissolution fluxes have a first-order dependence on the metal cation flux. The rate constant for oxide formation also follows an Arrhenius dependence on the potential drop across the oxide layer and hence decreases exponentially with oxide thickness. This model is able to predict the time-dependent potentiostatic corrosion behaviour of both pure iron, and Co–Cr and Fe–Ni–Cr alloys.

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Modelling of Corrosion Induced Stresses during Zircaloy-4 Oxidation in Air

Materials Science Forum ◽

10.4028/www.scientific.net/msf.595-598.419 ◽

2008 ◽

Vol 595-598 ◽

pp. 419-427 ◽

Cited By ~ 21

Author(s):

Vincent Busser ◽

Jean Desquines ◽

Stéphanie Fouquet ◽

Marie Christine Baietto ◽

Jean Paul Mardon

Keyword(s):

Oxide Layer ◽

Research Work ◽

Oxide Thickness ◽

Stress Profile ◽

Oxide Growth ◽

Large Set ◽

Transient Experiments ◽

Cracking Mechanisms ◽

Oxidation In Air ◽

Good Agreement

In the frame of its research work on nuclear fuel safety, the French “Institut de Radioprotection et de Sûreté Nucléaire” (IRSN) has highlighted the importance of cladding tube oxidation on its thermomechanical behavior. The occurrence of radial cracking and spallation has been observed as the main mechanisms for the zirconia layer degradation during transient experiments. A study of these two mechanisms has been jointly launched by IRSN and Areva-NP. Thus laboratory air oxidations of fully recrystallized or stress-relieved low-tin Zircaloy-4 cladding tubes have been performed. Representative oxide layer thicknesses varying from 10 to 100 0m have been obtained. SEM micrographs of the obtained oxidised samples show that short circumferential cracks are periodically distributed in the oxide thickness. For specimens with oxide film thickness greater than 30 0m, radial cracks are initiated from the outer surface of the oxide layer and propagated radially. Veins characterised by the lack of circumferentially orientated crack are evidenced. All these phenomena are mainly linked to high compressive stress levels in the zirconia layer. A model describing the stress evolution in the oxide and in the cladding has been developed. This model takes into account the influence of elasticity, cladding creep, oxide growth and thermal expansion. Deflection tests data [15] are used to calibrate the oxide growth modelling. The model enables the evaluation of strain or stress profile in the oxide layer and in the base metal. Numerical results are in good agreement with a large set of axial and circumferential strains measurements. Further a better understanding of cracking mechanisms is achieved considering the good agreement between experimental and numerical analysis.

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The growth of epitaxial uranium oxide observed by micro-Raman spectroscopy

MRS Proceedings ◽

10.1557/proc-0893-jj05-07 ◽

2005 ◽

Vol 893 ◽

Author(s):

Niña Caculitan ◽

Wigbert J. Siekhaus

Keyword(s):

Raman Spectroscopy ◽

Optical Properties ◽

Oxide Layer ◽

Uranium Oxide ◽

Signal Amplitude ◽

Oxide Thickness ◽

Grain Structure ◽

Raman Signal ◽

Oxide Growth ◽

Micro Raman Spectroscopy

AbstractRaman spectroscopy can be performed with micrometer resolution and can thus be used to determine the dependence of oxide thickness on the substrate’s grain structure or local impurity inclusions. The Raman signal amplitude emitted from an epitaxial uranium oxide layer as a function of oxide thickness has been modeled for light of 632.8 nm wavelength incident on the oxide and reflected from the uranium substrate using the optical properties determined by spectrophotometry. The model shows that the Raman signal increases with oxide thickness and saturates at about 150 nm thickness. The model was compared with the measured Raman signal amplitude of an epitaxial uranium oxide layer growing in air with a known time dependence of oxide growth.

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Correlation Between the Tunnelling Oxide and I-V Curves of MIS Photodiodes

MRS Proceedings ◽

10.1557/proc-762-a18.16 ◽

2003 ◽

Vol 762 ◽

Author(s):

H. Águas ◽

L. Pereira ◽

A. Goullet ◽

R. Silva ◽

E. Fortunato ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Oxide Layer ◽

Spectroscopic Ellipsometry ◽

Chemical Deposition ◽

Oxide Thickness ◽

Electrical Performance ◽

Signal To Noise ◽

Rectification Factor ◽

Mis Devices ◽

The Ideal

AbstractIn this work we present results of a study performed on MIS diodes with the following structure: substrate (glass) / Cr (2000Å) / a-Si:H n+ (400Å) / a-Si:H i (5500Å) / oxide (0-40Å) / Au (100Å) to determine the influence of the oxide passivation layer grown by different techniques on the electrical performance of MIS devices. The results achieved show that the diodes with oxides grown using hydrogen peroxide present higher rectification factor (2×106)and signal to noise (S/N) ratio (1×107 at -1V) than the diodes with oxides obtained by the evaporation of SiO2, or by the chemical deposition of SiO2 by plasma of HMDSO (hexamethyldisiloxane), but in the case of deposited oxides, the breakdown voltage is higher, 30V instead of 3-10 V for grown oxides. The ideal oxide thickness, determined by spectroscopic ellipsometry, is dependent on the method used to grow the oxide layer and is in the range between 6 and 20 Å. The reason for this variation is related to the degree of compactation of the oxide produced, which is not relevant for applications of the diodes in the range of ± 1V, but is relevant when high breakdown voltages are required.

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Effect of the Niobium-Doped Titanium Oxide Thickness and Thermal Oxide Layer for Silicon Quantum Dot Solar Cells as a Dopant-Blocking Layer

Nanoscale Research Letters ◽

10.1186/s11671-020-3272-8 ◽

2020 ◽

Vol 15 (1) ◽

Cited By ~ 2

Author(s):

Ryushiro Akaishi ◽

Kohei Kitazawa ◽

Kazuhiro Gotoh ◽

Shinya Kato ◽

Noritaka Usami ◽

...

Keyword(s):

Solar Cells ◽

Quantum Dot ◽

Oxide Layer ◽

Titanium Oxide ◽

Oxide Thickness ◽

Blocking Layer ◽

Silicon Quantum Dot ◽

Quantum Dot Solar Cells ◽

Thermal Oxide ◽

Niobium Doped

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The Atmosphere’s Effect on Stainless Steel Slabs’ Oxide Formation in a CH4-Fuelled Reheating Furnace

Metals ◽

10.3390/met11040621 ◽

2021 ◽

Vol 11 (4) ◽

pp. 621

Author(s):

Aleksi Laukka ◽

Eetu-Pekka Heikkinen ◽

Timo Fabritius

Keyword(s):

Stainless Steel ◽

Oxide Layer ◽

Depth Profiling ◽

Layer Growth ◽

304 Stainless Steel ◽

Oxide Growth ◽

Breakaway Oxidation ◽

Positive Effects ◽

Steel Slab ◽

Single Temperature

Utilising the oxyfuel practice for CH4-fuelled combustion has positive effects on the emissions, efficiency and cost of high temperature furnace practices. However, especially in older installations, oxyfuel usage requires retrofitting and alters the atmosphere in which the oxidation of the steel occurs, when compared to using air as the oxidiser. Stainless steel slab oxide growth during reheating was studied in different atmospheres. The simulated post-burn atmospheres from oxyfuel, lean oxyfuel and air-fuel practices were used to compare oxide-scale layer growth and morphology during simulated typical AISI 304 stainless steel slab reheating prior to hot rolling. Thermogravimetric measurements, glow discharge optical emission spectrometer (GDOES) and field-emission scanning electron microscope energy dispersive X-ray (FESEM-EDS) methodology were applied to discern differences between oxide growth and inner oxide layer morphology between the three practices. Switching from air to oxyfuel practice at a single temperature had the same increasing effect on the scale formation amount as a 25 °C temperature increase in air atmosphere. Inner oxide layer depth profiling revealed C, Si and Ni to be the main elements that differed between temperatures and atmospheres. A morphology study showed Si and Ni behaviour to be linked to breakaway oxidation.

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Improving the accuracy of the charge-sheet model for the long-channel metal-oxide semiconductor field-effect transistor

Canadian Journal of Physics ◽

10.1139/p87-159 ◽

1987 ◽

Vol 65 (8) ◽

pp. 995-998

Author(s):

N. G. Tarr

Keyword(s):

Metal Oxide ◽

Field Effect ◽

Field Effect Transistor ◽

Inversion Layer ◽

Potential Drop ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Analytic Approximation ◽

Effect Transistor ◽

Long Channel

It is shown that the accuracy of the charge-sheet model for the long-channel metal-oxide-semiconductor field-effect transistor can be improved by allowing for the small potential drop across the inversion layer, and by using a more accurate analytic approximation for the charge stored in the depletion region.

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Comparative Study ofSiO2,Al2O3, and BeO Ultrathin Interfacial Barrier Layers in Si Metal-Oxide-Semiconductor Devices

Active and Passive Electronic Components ◽

10.1155/2012/359580 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

J. H. Yum ◽

J. Oh ◽

Todd. W. Hudnall ◽

C. W. Bielawski ◽

G. Bersuker ◽

...

Keyword(s):

Metal Oxide ◽

High Performance ◽

Field Effect Transistors ◽

Beryllium Oxide ◽

Atomic Layer ◽

Oxide Thickness ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Flat Band ◽

Effective Electron

In a previous study, we have demonstrated that beryllium oxide (BeO) film grown by atomic layer deposition (ALD) on Si and III-V MOS devices has excellent electrical and physical characteristics. In this paper, we compare the electrical characteristics of inserting an ultrathin interfacial barrier layer such as SiO2, Al2O3, or BeO between the HfO2gate dielectric and Si substrate in metal oxide semiconductor capacitors (MOSCAPs) and n-channel inversion type metal oxide semiconductor field effect transistors (MOSFETs). Si MOSCAPs and MOSFETs with a BeO/HfO2gate stack exhibited high performance and reliability characteristics, including a 34% improvement in drive current, slightly better reduction in subthreshold swing, 42% increase in effective electron mobility at an electric field of 1 MV/cm, slightly low equivalent oxide thickness, less stress-induced flat-band voltage shift, less stress induced leakage current, and less interface charge.

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Combined Effects of Overheating and Soot-Blower Erosion on Reheater Tubing in a Gas-Fired Large Capacity Boiler

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2795769 ◽

2008 ◽

Vol 130 (2) ◽

Author(s):

Nasr M. Hosny

Keyword(s):

Data Analysis ◽

Oxide Layer ◽

Test Data ◽

Gas Flow ◽

Combined Effects ◽

Unit Operation ◽

Metal Oxidation ◽

Flow Temperature ◽

Large Capacity ◽

Short Time

In a large capacity tangentially fired boiler, the final reheater tubing sustained abnormal oxidation and localized excessive metal wastage in a short time of the unit operation. The root causes of the problem are identified by test data analysis. The test data indicated that the reheater tubing metal temperatures in the affected areas exceeded the recommended limit of the metal oxidation temperature due to higher than expected local gas temperatures and velocities. A soot-blower facing the overheated portion of the reheater leading tubes accelerated the process of metal wastage by periodically removing the oxide layer. The configuration of the boiler internals upstream of the reheater section is found to be the main cause of the localized overheating. Side-to-side gas flow/temperature stratification due to tangential firing contributed to a lesser degree to the problem. The results and conclusions presented in this paper should be a beneficial guide to the designer of large capacity boilers.

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Material Property of a Passive Oxide Formed on Alloy 600

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.26-28.937 ◽

2007 ◽

Vol 26-28 ◽

pp. 937-940 ◽

Cited By ~ 2

Author(s):

Dong Jin Kim ◽

Hyuk Chul Kwon ◽

Seong Sik Hwang ◽

Hong Pyo Kim

Keyword(s):

Corrosion Resistance ◽

Oxide Layer ◽

Passive Film ◽

Electrochemical Impedance ◽

Oxide Films ◽

Oxide Thickness ◽

Solution Temperature ◽

Alloy 600 ◽

Pressurized Water ◽

Electrochemical Behaviors

Alloy 600 is used as a material for a steam generator tubing in pressurized water reactors(PWR) due to its high corrosion resistance under a PWR environment. In spite of its corrosion resistance, a stress corrosion cracking(SCC) has occurred on the primary side as well as the secondary side of a tubing. It is known that a SCC is related to the electrochemical behaviors of an anodic dissolution and a passivation of a bare surface of metals and alloys. Therefore in the present work, the passive oxide films on Alloy 600 have been investigated as a function of the solution temperature by using a potentiodynamic polarization, electrochemical impedance spectroscopy and a TEM, equipped with EDS. Moreover the semiconductive property was evaluated by using the Mott-Schottky relation. It was found that the passivity depends on the chemical composition and the densification of the oxide film rather than the oxide thickness. As the solution temperature of 0.5M H3BO3 increased, the thickness of the passive film increased but the oxide resistance of the passive film was decreased, indicating that the measured current in the passive region of the potentiodynamic curve is closely related to the stability of the passive film rather than the oxide thickness. It was found that the oxide films were composed of an outer oxide layer with a lower resistance and an inner oxide layer with a relatively higher resistance. From the Mott-Schottky relation, the oxide formed at 300oC showed a p-type semiconductor property unlike the n-type oxide films up to 250oC.

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