The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Y F Cheng - One of the best experts on this subject based on the ideXlab platform.
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effect of strain rate on cathodic Reaction during stress Corrosion cracking of x70 pipeline steel in a near neutral ph solution
Journal of Materials Engineering and Performance, 2011Co-Authors: Zhiyong Liu, Y F ChengAbstract:The effect of strain rate on cathodic Reactions of X70 pipeline steel during stress Corrosion cracking in a near-neutral pH solution was investigated by electrochemical impedance spectroscope and potentiodynamic polarization curve measurements as well as slow strain rate tests. A local additional potential model was used to understand mechanistically the role of strain rate in electrochemical cathodic Reaction. It was found that an application of elastic stress would not affect the electrochemical stable state of the steel specimen at a macroscopic scale. Under a weak cathodic polarization, the interfacial charge-transfer process occurring on steel contains both cathodic and anodic Reactions. Since the anodic Reaction process is still significant, localized dissolution could occur even at such a cathodic potential, resulting in generation of Corrosion pits. These pits could be the start sites to initiate stress Corrosion cracks. Strain rate affects the Corrosion Reaction, which is associated with the generation of dislocation emergence points and slip steps on the specimen surface, resulting in a negative local additional potential to enhance the cathodic Reaction locally.
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mechanistic aspects of electrochemical Corrosion of aluminum alloy in ethylene glycol water solution
Electrochimica Acta, 2008Co-Authors: Guoan Zhang, Y F ChengAbstract:Abstract The electrochemical Corrosion behavior of 3003 aluminum (Al) alloy in ethylene glycol–water solutions was studied by electrochemical measurements and surface analysis techniques through an impingement jet system. Al Corrosion in aerated, stationary solution is a mixed-controlled process, i.e., both activation and mass-transfer steps control the Corrosion Reaction. Upon flowing of solution, no matter if sand particles are contained, Al Corrosion is an activation-controlled process. In addition to Al oxide film, a layer of Al-alcohol film will also be formed on the electrode surface in ethylene glycol–water solution, contributing to inhibition of anodic dissolution of Al. In the absence of oxygen, a stable passivity could also be achieved on Al alloy. The main cathodic Reaction is either reduction of water or reduction of ethylene glycol. However, the reduction of water and ethylene glycol would not be as significant as that of oxygen. As a consequence, the resultant film is not as stable as that formed in the presence of oxygen, as shown in polarization measurements. Al Corrosion Reaction in mixed-controlled by activation step and mass-transfer step through the anodic surface film. The coverage of the adsorbed intermediate product on Al electrode surface is expected to be very small under the impingement of fluid and sand particles, which results in the generation of an inductive loop in Nyquist diagrams measured on Al electrode in ethylene glycol–water solution.
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Corrosion of steel under the defected coating studied by localized electrochemical impedance spectroscopy
Electrochimica Acta, 2008Co-Authors: Cheng Zhong, X Tang, Y F ChengAbstract:Abstract Corrosion of steel under the defected coating in near-neutral pH solution was investigated by localized electrochemical impedance spectroscopy (LEIS) measurements. The LEIS response is dependent on the size of the defect. For small defects, e.g., less than 200 μm in diameter, localized Corrosion process and mechanism of steel, as indicated by the measured LEIS plots, change with time. The diffusion process dominates the interfacial Corrosion Reaction, which is due to the block effect of the deposited Corrosion product combined with the geometrical factor of a large coating thickness/defect width ratio. In the presence of a big defect, e.g., up to 1000 μm, the LEIS responses measured at the defect are always featured by a coating impedance in the high-frequency range and an interfacial Corrosion Reaction in the low-frequency range. The block effect of Corrosion product does not apply due to the relatively open geometry. Conventional EIS measurements on a macroscopic-coated electrode reflect the “averaged” impedance results from both coating and defect. The information of the localized electrochemical Corrosion processes and mechanisms at the small defect is lost, and the coating impedance information is “averaged” out when a big defect is contained. LEIS measurement provides an essential technique to characterize microscopically the local electrochemical Corrosion Reaction of steel under the defected coating.
Zhiyong Liu - One of the best experts on this subject based on the ideXlab platform.
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effect of strain rate on cathodic Reaction during stress Corrosion cracking of x70 pipeline steel in a near neutral ph solution
Journal of Materials Engineering and Performance, 2011Co-Authors: Zhiyong Liu, Y F ChengAbstract:The effect of strain rate on cathodic Reactions of X70 pipeline steel during stress Corrosion cracking in a near-neutral pH solution was investigated by electrochemical impedance spectroscope and potentiodynamic polarization curve measurements as well as slow strain rate tests. A local additional potential model was used to understand mechanistically the role of strain rate in electrochemical cathodic Reaction. It was found that an application of elastic stress would not affect the electrochemical stable state of the steel specimen at a macroscopic scale. Under a weak cathodic polarization, the interfacial charge-transfer process occurring on steel contains both cathodic and anodic Reactions. Since the anodic Reaction process is still significant, localized dissolution could occur even at such a cathodic potential, resulting in generation of Corrosion pits. These pits could be the start sites to initiate stress Corrosion cracks. Strain rate affects the Corrosion Reaction, which is associated with the generation of dislocation emergence points and slip steps on the specimen surface, resulting in a negative local additional potential to enhance the cathodic Reaction locally.
Chang Woo Lee - One of the best experts on this subject based on the ideXlab platform.
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Improving self-discharge and anti-Corrosion performance of Zn-air batteries using conductive polymer-coated Zn active materials
Journal of Industrial and Engineering Chemistry, 2019Co-Authors: P. Santhoshkumar, K. Prasanna, Kumaran Vediappan, Chang Woo LeeAbstract:Abstract The Corrosion and hydrogen evolution Reactions of Zn anodes accelerate the self-discharge of a Zn-air battery. To suppress the Corrosion Reaction and improve the self-discharge behavior of a Zn-air battery, polyaniline (PANI) is synthesized with different amounts of 0.1 M sulfuric acid and coated on a Zn surface. The PANI-coated materials effectively suppress the Corrosion Reaction, and the Zn-air cells prepared with PANI-coated Zn materials exhibit enhanced self-discharge behavior. The specific discharge capacity after 24 h storage and capacity retention of Zn were 520.2 mA h/g and 74.4%, respectively. Whereas the PANI-coated Zn (100 ml sulfuric acid) shows 565.3 mA h/g of specific discharge capacity after 24 h storage, 75.8% Corrosion inhibition efficiency and 96.9% capacity retention. Therefore, PANI-coated Zn materials are effective in suppressing the Corrosion Reaction and improving self-discharge behaviors in Zn-air batteries.
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preliminary comparative studies of zinc and zinc oxide electrodes on Corrosion Reaction and reversible Reaction for zinc air fuel cells
Electrochimica Acta, 2006Co-Authors: Chang Woo Lee, Seung Wook Eom, Kulathu Iyer Sathiyanarayanan, Mun Soo YunAbstract:Even though Zn/air energy system is considered to be a promising power energy source, it has been limited to be applied for an electrically rechargeable system basically due to the problem of the irreversible Reaction and the Corrosion Reaction. In this paper a novel attempt has been made to compare the behavior of zinc electrode with a zinc oxide electrode and a modified zinc oxide electrode containing zinc oxide and lead oxide. The hydrogen overpotential is favorable in the zinc electrode, and the modified zinc oxide electrode shows the improved properties showing the more negative potential than the case of the zinc oxide electrode. Investigations of cyclic voltammogram reveal that the pure zinc electrode is irreversible, while both the zinc oxide and the modified zinc oxide electrodes are reversible. However, as far as dendrite formation is concerned there is no marked improvement in case of the zinc oxide and the modified zinc oxide electrodes.
S R Ryan - One of the best experts on this subject based on the ideXlab platform.
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a mechanistic study of the uniform Corrosion of copper in compacted na montmorillonite s and mixtures
Corrosion Science, 1992Co-Authors: F. King, C D Litke, S R RyanAbstract:Abstract The uniform Corrosion behaviour of copper has been studied in environments similar to those expected in a Canadian nuclear fuel waste disposal vault. Under the experimental conditions used, the rate of Corrosion is limited by the diffusion of copper through the compacted clay-sand buffer material that will surround the nuclear waste containers. The extent of the copper diffusion process was determined at the end of each test by measuring the copper concentration profile in the buffer material. In the presence of γ-radiation, the copper diffused further than in the unirradiated tests, but the Corrosion rate was lower. Rate control by copper diffusion can account for both of these effects, with the effect of γ-radiation being to reduce the extent of sorption of copper by the clay. The results are consistent with a mass transport controlled Corrosion Reaction dominated by pore-water diffusion in the presence of γ-radiation and surface-water diffusion in the absence of radiation.
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A mechanistic study of the uniform Corrosion of copper in compacted Na-montmorillonite/s and mixtures
Corrosion Science, 1992Co-Authors: F. King, C D Litke, S R RyanAbstract:Abstract The uniform Corrosion behaviour of copper has been studied in environments similar to those expected in a Canadian nuclear fuel waste disposal vault. Under the experimental conditions used, the rate of Corrosion is limited by the diffusion of copper through the compacted clay-sand buffer material that will surround the nuclear waste containers. The extent of the copper diffusion process was determined at the end of each test by measuring the copper concentration profile in the buffer material. In the presence of γ-radiation, the copper diffused further than in the unirradiated tests, but the Corrosion rate was lower. Rate control by copper diffusion can account for both of these effects, with the effect of γ-radiation being to reduce the extent of sorption of copper by the clay. The results are consistent with a mass transport controlled Corrosion Reaction dominated by pore-water diffusion in the presence of γ-radiation and surface-water diffusion in the absence of radiation.
R F Edlich - One of the best experts on this subject based on the ideXlab platform.
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Corrosion of stainless steel pipes in a hydrotherapy pool by a silver-copper disinfection system.
The Journal of burn care & rehabilitation, 1995Co-Authors: N D Nguyen, H N Wadley, R F EdlichAbstract:The silver-copper disinfection system has been shown to be effective for water purification. It emits silver ions that combine with bacteria, causing their death. While disinfecting the water, these silver ions exhibit adverse effects on the stainless steel pipes in hydrotherapy pools. In an oxidation-reduction Reaction the silver ions are converted into solid silver that is deposited on stainless steel, causing a Corrosion Reaction. The corroded steel has a black deposit that readily adheres to the burned patient's skin.
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Corrosion of stainless steel pipes in a hydrotherapy pool by a silver-copper disinfection system.
Journal of Burn Care & Rehabilitation, 1995Co-Authors: N D Nguyen, H N Wadley, R F EdlichAbstract:The silver-copper disinfection system has been shown to be effective for water purification. It emits silver ions that combine with bacteria, causing their death. While disinfecting the water, these silver ions exhibit adverse effects on the stainless steel pipes in hydrotherapy pools. In an oxidation-reduction Reaction the silver ions are converted into solid silver that is deposited on stainless steel, causing a Corrosion Reaction. The corroded steel has a black deposit that readily adheres to the burned patient's skin. ( J BURN CARE REHABIL
