AA2024-T3 are widely used in various applications because of their exceptional physical properties. However, they are susceptible to corrosion and cavitation erosion in aggressive environments due to high concentration of copper. Sol-gel coatings in the field of corrosion prevention are emerging. Improved thickness of coatings significantly improves the barrier effect of the coatings, thereby improving their operational-life in industrial applications. To date, a limited amount of work has been carried out in determining the effect of hybrid sol-gel coatings on abrasion and cavitation erosion of AA2024-T3. The present study investigates the effect of thickness of the coatings on morphology, corrosion, abrasion and cavitation erosion properties of the prepared hybrid sol-gel coatings deposited on AA2024-T3 surfaces. The hybrid sol-gels have been synthesized from 3-trimethoxysilylpropylmethacrylate (MAPTMS), and a zirconium complex prepared from the chelation of zirconium n-propoxide (ZPO), and methacrylic acid (MAAH). AA-2024 T3 were coated using single-dip, double-dip and triple-dip. Abrasion and cavitation erosion tests were performed according to the relevant standards. Structural damage caused by corrosion, abrasion and cavitation erosion was studied by Optical Microscope and Scanning Electron Microscope (SEM). Corrosion protection performance of the coatings was tested using Open Circuit Potential (OCP) and Potentiodynamic polarization (PDS). Results indicated that the multilayer coated samples improved the corrosion, cavitation erosion and abrasion resistance of AA2024-T3. Hence, the prepared silica-based coatings can be proposed as a potential choice for marine renewable energy applications.
{"title":"Abrasion and Cavitation Erosion Resistance of Multi-Layer Dip Coated Sol-Gel Coatings on AA2024-T3","authors":"M. Hegde, Y. Kavanagh, B. Duffy, E. Tobin","doi":"10.3390/cmd3040036","DOIUrl":"https://doi.org/10.3390/cmd3040036","url":null,"abstract":"AA2024-T3 are widely used in various applications because of their exceptional physical properties. However, they are susceptible to corrosion and cavitation erosion in aggressive environments due to high concentration of copper. Sol-gel coatings in the field of corrosion prevention are emerging. Improved thickness of coatings significantly improves the barrier effect of the coatings, thereby improving their operational-life in industrial applications. To date, a limited amount of work has been carried out in determining the effect of hybrid sol-gel coatings on abrasion and cavitation erosion of AA2024-T3. The present study investigates the effect of thickness of the coatings on morphology, corrosion, abrasion and cavitation erosion properties of the prepared hybrid sol-gel coatings deposited on AA2024-T3 surfaces. The hybrid sol-gels have been synthesized from 3-trimethoxysilylpropylmethacrylate (MAPTMS), and a zirconium complex prepared from the chelation of zirconium n-propoxide (ZPO), and methacrylic acid (MAAH). AA-2024 T3 were coated using single-dip, double-dip and triple-dip. Abrasion and cavitation erosion tests were performed according to the relevant standards. Structural damage caused by corrosion, abrasion and cavitation erosion was studied by Optical Microscope and Scanning Electron Microscope (SEM). Corrosion protection performance of the coatings was tested using Open Circuit Potential (OCP) and Potentiodynamic polarization (PDS). Results indicated that the multilayer coated samples improved the corrosion, cavitation erosion and abrasion resistance of AA2024-T3. Hence, the prepared silica-based coatings can be proposed as a potential choice for marine renewable energy applications.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86950810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reinforcement corrosion is the risk most frequently cited to justify concrete durability research, especially where it is induced by chlorides. Surface-applied corrosion inhibitors are widely used to mitigate the corrosion process both for carbonation and chlorides of steel reinforcement in concrete. They are applied onto the surface of hardened concrete and penetrate towards steel reinforcement. This paper discusses the corrosion inhibition performance of a new generation of a dual-phase surface-applied corrosion inhibitor (DP-SACI), and its efficiency in corrosion induced by chlorides over 3% referred to cement mass, and also in pre- and post-cracked structures. This corrosion mitigation activity was evaluated onsite for almost four years, in a sea wall exposed to XS1 ambiance. The electrochemical techniques used were based on the determination of the electrical resistivity of concrete, the half-cell corrosion potential and the steel corrosion rate (from linear polarization resistance measurements). All of these electrochemical parameters provide accurate information for on-site structures about the efficiency over the time of surface-applied corrosion inhibitors. The effectiveness of the dual-phase surface-applied corrosion inhibitor proved to be up to 99%, even with ongoing corrosion and 0.3 mm cracks near the rebar. The use of DP-SACI provides a non-destructive repair method that inhibits the corrosion process and increases the service life of the element.
{"title":"Protection of Reinforced Concrete Steel Exposed to a Marine Environment: A Preliminary Onsite Study of the Performance of a New Generation of Surface-Applied Corrosion Inhibitors","authors":"D. Martin, E. Seyhan","doi":"10.3390/cmd3040034","DOIUrl":"https://doi.org/10.3390/cmd3040034","url":null,"abstract":"Reinforcement corrosion is the risk most frequently cited to justify concrete durability research, especially where it is induced by chlorides. Surface-applied corrosion inhibitors are widely used to mitigate the corrosion process both for carbonation and chlorides of steel reinforcement in concrete. They are applied onto the surface of hardened concrete and penetrate towards steel reinforcement. This paper discusses the corrosion inhibition performance of a new generation of a dual-phase surface-applied corrosion inhibitor (DP-SACI), and its efficiency in corrosion induced by chlorides over 3% referred to cement mass, and also in pre- and post-cracked structures. This corrosion mitigation activity was evaluated onsite for almost four years, in a sea wall exposed to XS1 ambiance. The electrochemical techniques used were based on the determination of the electrical resistivity of concrete, the half-cell corrosion potential and the steel corrosion rate (from linear polarization resistance measurements). All of these electrochemical parameters provide accurate information for on-site structures about the efficiency over the time of surface-applied corrosion inhibitors. The effectiveness of the dual-phase surface-applied corrosion inhibitor proved to be up to 99%, even with ongoing corrosion and 0.3 mm cracks near the rebar. The use of DP-SACI provides a non-destructive repair method that inhibits the corrosion process and increases the service life of the element.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86886116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arumugam Madhan Kumar, A. Adesina, Jothi Veeramani, M. Rahman, J. S. Nirmal Ram
Hybrid treatments consisting of surface modification and subsequent protective coatings have gained extensive attention among corrosion mitigation approaches for a wide variety of structural metallic materials. This study aims to review the enhancement of the corrosion protection performance of polyurethane (PU) coatings on 316L stainless steel (SS) specimens. This was achieved via a two-step strategic treatment, primarily by electrochemical passivation and subsequent deposition of PU composite coatings with the different feed ratio of synthesized polypyrrole (PPy) nanoparticles. The effect of different applied voltage on the surface features and the corrosion behavior of the passivated SS surfaces was systematically investigated using surface characterization techniques and a potentiodynamic polarization test in a NaCl solution. Surface morphological images revealed the porous structure on the passivated surface. It is inferred from the topographical surface results that homogeneous surface roughness was achieved with the applied voltage of 5 V. Infra-red spectroscopic results validate the formation of PU/PPy composite coatings and the intermolecular chemical interaction between the PU and PPy moieties. Furthermore, corrosion measurements corroborate the improved corrosion resistance of PU/30PPy coatings with higher values of charge transfer resistance, Rct (1.0869 × 107 Ω cm2), and film resistance, Rf (2.258 × 105 Ω cm2), with the lowest values of corrosion, icorr (4.7 × 10−3 µA cm−2) compared to that of the PU/Bare specimen. In conclusion, it is confirmed that the passivated surface enhances the corrosion resistance performance of PU coated SS, and this performance is further increased with the incorporation of PPy particles.
{"title":"Hybrid Polyurethane/Polypyrrole Composite Coatings on Passivated 316L SS for Surface Protective Action against Corrosion in Saline Medium","authors":"Arumugam Madhan Kumar, A. Adesina, Jothi Veeramani, M. Rahman, J. S. Nirmal Ram","doi":"10.3390/cmd3040033","DOIUrl":"https://doi.org/10.3390/cmd3040033","url":null,"abstract":"Hybrid treatments consisting of surface modification and subsequent protective coatings have gained extensive attention among corrosion mitigation approaches for a wide variety of structural metallic materials. This study aims to review the enhancement of the corrosion protection performance of polyurethane (PU) coatings on 316L stainless steel (SS) specimens. This was achieved via a two-step strategic treatment, primarily by electrochemical passivation and subsequent deposition of PU composite coatings with the different feed ratio of synthesized polypyrrole (PPy) nanoparticles. The effect of different applied voltage on the surface features and the corrosion behavior of the passivated SS surfaces was systematically investigated using surface characterization techniques and a potentiodynamic polarization test in a NaCl solution. Surface morphological images revealed the porous structure on the passivated surface. It is inferred from the topographical surface results that homogeneous surface roughness was achieved with the applied voltage of 5 V. Infra-red spectroscopic results validate the formation of PU/PPy composite coatings and the intermolecular chemical interaction between the PU and PPy moieties. Furthermore, corrosion measurements corroborate the improved corrosion resistance of PU/30PPy coatings with higher values of charge transfer resistance, Rct (1.0869 × 107 Ω cm2), and film resistance, Rf (2.258 × 105 Ω cm2), with the lowest values of corrosion, icorr (4.7 × 10−3 µA cm−2) compared to that of the PU/Bare specimen. In conclusion, it is confirmed that the passivated surface enhances the corrosion resistance performance of PU coated SS, and this performance is further increased with the incorporation of PPy particles.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82199145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The variability found in real structures is a function of the “intrinsic” variability of the material itself, of its aging with time and of the external climatic conditions, and, therefore, it is normal that the chloride threshold and the corrosion rates could vary spatially in the same structure or temporarily as the concrete ages. In present communication, some statistical distributions of chloride threshold are discussed, as well as the variability of the corrosion rate in real exposure conditions. In all both cases, the values found in laboratory specimens are in the same range than those found in real structures. The chloride threshold can vary from 0.2% to around 3% by weight of cement depending on the corrosion potential, which, in turn, depends on the particular condition of the steel bar in each structure. The corrosion rates show to be below 0.1 µA/cm2 when the steel is passive and values above 1 µA/cm2 are seldom found in real structures. The high variability when considering all choices may impact in a prediction of residual life of several decades of difference which aims into the need for the assessment of a specialized engineering judgement in function of the quality of the concrete and the exposure class.
{"title":"Statistical Treatments of Chloride Threshold and Corrosion Propagation Rate","authors":"C. Andrade, D. Izquierdo","doi":"10.3390/cmd3040032","DOIUrl":"https://doi.org/10.3390/cmd3040032","url":null,"abstract":"The variability found in real structures is a function of the “intrinsic” variability of the material itself, of its aging with time and of the external climatic conditions, and, therefore, it is normal that the chloride threshold and the corrosion rates could vary spatially in the same structure or temporarily as the concrete ages. In present communication, some statistical distributions of chloride threshold are discussed, as well as the variability of the corrosion rate in real exposure conditions. In all both cases, the values found in laboratory specimens are in the same range than those found in real structures. The chloride threshold can vary from 0.2% to around 3% by weight of cement depending on the corrosion potential, which, in turn, depends on the particular condition of the steel bar in each structure. The corrosion rates show to be below 0.1 µA/cm2 when the steel is passive and values above 1 µA/cm2 are seldom found in real structures. The high variability when considering all choices may impact in a prediction of residual life of several decades of difference which aims into the need for the assessment of a specialized engineering judgement in function of the quality of the concrete and the exposure class.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84816739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent progress is reviewed. Recent developments include: (i) accumulation of evidence that electrochemical measurements of the Mg corrosion rate often do not agree with the steady state Mg corrosion rate as measured by weight loss; (ii) low Fe tolerance limits are caused by heat treatment of nominally high-purity Mg and the presence of Si, (iii) the intrinsic Mg corrosion rate is 0.3 mm/y in a chloride solution as measured by weight loss, (iv) there are many Mg alloys with corrosion rates between 0.3 and 1.0 mm/y, (v) there are few Mg alloys with corrosion rates less than 0.3 mm/y, (vi) experimental evidence contradicts the enhanced catalytic activity mechanism of Mg corrosion, (vii) experiments support the uni-positive Mg+ mechanism, (viii) new compelling experimental evidence supporting the uni-positive Mg+ corrosion mechanism has been provided by electrochemical impedance spectroscopy (EIS), and (ix) the uni-positive Mg+ corrosion mechanism provides new insights for understanding the performance of Mg-air batteries and for the development of better Mg anodes.
{"title":"Mg Corrosion—Recent Progress","authors":"A. Atrens, Xingrui Chen, Z. Shi","doi":"10.3390/cmd3040031","DOIUrl":"https://doi.org/10.3390/cmd3040031","url":null,"abstract":"Recent progress is reviewed. Recent developments include: (i) accumulation of evidence that electrochemical measurements of the Mg corrosion rate often do not agree with the steady state Mg corrosion rate as measured by weight loss; (ii) low Fe tolerance limits are caused by heat treatment of nominally high-purity Mg and the presence of Si, (iii) the intrinsic Mg corrosion rate is 0.3 mm/y in a chloride solution as measured by weight loss, (iv) there are many Mg alloys with corrosion rates between 0.3 and 1.0 mm/y, (v) there are few Mg alloys with corrosion rates less than 0.3 mm/y, (vi) experimental evidence contradicts the enhanced catalytic activity mechanism of Mg corrosion, (vii) experiments support the uni-positive Mg+ mechanism, (viii) new compelling experimental evidence supporting the uni-positive Mg+ corrosion mechanism has been provided by electrochemical impedance spectroscopy (EIS), and (ix) the uni-positive Mg+ corrosion mechanism provides new insights for understanding the performance of Mg-air batteries and for the development of better Mg anodes.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91067773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many heritage objects consist of glass in contact with metals. By ion exchange with absorbed water, alkaline aqueous films are formed on the glass surface. They contain sodium and/or potassium, hydroxide, and carbonate (uptake of carbon dioxide) ions. These electrolytes induce corrosion while in contact with metal. Surprisingly, this phenomenon has only been realised by research in Stuttgart in the last two decades. About 350 affected objects were detected in the meantime in a number of heritage collections. Because of the special electrolytes, unusual corrosion products are often formed. The unknown structure and formula of three of them could be determined by modern X-ray powder diffraction data evaluation. One example is the basic potassium lead carbonate, KOH‧2PbCO3, detected on a pewter lid of a glass jug. The sodium analogon of already known structure was found in hollow glass balls mirrored on the inside with molten lead. Chalconatronite, Na2[Cu(CO3)2]‧3H2O, is known as a corrosion product of copper alloys in contact with soda solutions (here: from glass degradation). Exposed to acetic acid emissions (e.g., from wood), it transforms to a sodium copper acetate carbonate of hitherto undetermined structure. The ubiquitous pollutant formaldehyde reacts directly to formate in the alkaline medium provided by glass degradation. On copper alloys in contact with glass, formates are, therefore, frequent: Na4Cu4O(HCOO)8(OH)2‧4H2O in 50% of all cases and in 33% Cu2(HCOO)(OH)3. Zinc (from brass) forms Zn(HCOO)2‧2H2O and Zn4Cu3(Zn1−xCux)6(HCOO)8 (OH)18·6H2O. There are a number of other corrosion products, e.g., containing zinc and carboxylates awaiting further characterisation. Preventive conservation needs to slow down corrosion by dry storage (not lower than 35% rH). Pollutants need to be avoided by careful selection of materials for storage, display, and conservation.
{"title":"Curious Corrosion Compounds Caused by Contact: A Review of Glass-Induced Metal Corrosion on Museum Exhibits (GIMME)","authors":"G. Eggert, Andrea Fischer","doi":"10.3390/cmd3030030","DOIUrl":"https://doi.org/10.3390/cmd3030030","url":null,"abstract":"Many heritage objects consist of glass in contact with metals. By ion exchange with absorbed water, alkaline aqueous films are formed on the glass surface. They contain sodium and/or potassium, hydroxide, and carbonate (uptake of carbon dioxide) ions. These electrolytes induce corrosion while in contact with metal. Surprisingly, this phenomenon has only been realised by research in Stuttgart in the last two decades. About 350 affected objects were detected in the meantime in a number of heritage collections. Because of the special electrolytes, unusual corrosion products are often formed. The unknown structure and formula of three of them could be determined by modern X-ray powder diffraction data evaluation. One example is the basic potassium lead carbonate, KOH‧2PbCO3, detected on a pewter lid of a glass jug. The sodium analogon of already known structure was found in hollow glass balls mirrored on the inside with molten lead. Chalconatronite, Na2[Cu(CO3)2]‧3H2O, is known as a corrosion product of copper alloys in contact with soda solutions (here: from glass degradation). Exposed to acetic acid emissions (e.g., from wood), it transforms to a sodium copper acetate carbonate of hitherto undetermined structure. The ubiquitous pollutant formaldehyde reacts directly to formate in the alkaline medium provided by glass degradation. On copper alloys in contact with glass, formates are, therefore, frequent: Na4Cu4O(HCOO)8(OH)2‧4H2O in 50% of all cases and in 33% Cu2(HCOO)(OH)3. Zinc (from brass) forms Zn(HCOO)2‧2H2O and Zn4Cu3(Zn1−xCux)6(HCOO)8 (OH)18·6H2O. There are a number of other corrosion products, e.g., containing zinc and carboxylates awaiting further characterisation. Preventive conservation needs to slow down corrosion by dry storage (not lower than 35% rH). Pollutants need to be avoided by careful selection of materials for storage, display, and conservation.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75839294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Saad E. Kaskah, Gitta Ehrenhaft, J. Gollnick, C. Fischer
To investigate the corrosion protection behavior of naturally derived cocoyl sarcosine in combination with N-b-hydroxyethyl oleyl imidazole for steel CR4 in 0.1 M NaCl, different evaluation systems (weight loss, electrochemical measurements, and spray corrosion tests) were used. Both compounds were tested in different concentrations (25–100 mmol/L) and with variable dip coating times (1–30 min), first individually and then in combination, to check any synergistic effects for surface protection. Both showed only an insignificant corrosion inhibiting effect with less than 50% efficiency at all concentrations and dip coating times if used alone. In contrast, compound combinations revealed an improved corrosion inhibition correlated with higher concentrations. Across all methods, the compound combination concentration of 100 mmol/L resulted in improved efficiency of up to 83% for gravimetric tests, up to 84% for the impedance measure and more than 91% for potentiodynamic polarization. Dip coating variations proved 10 min to be the best option for all compounds with a maximum efficiency of up to 86% for the compound combination.
为了研究天然衍生的椰基肌氨酸与n -b-羟乙基油酰咪唑在0.1 M NaCl中对CR4钢的防腐性能，采用了不同的评价体系(失重、电化学测量和喷雾腐蚀试验)。两种化合物在不同浓度(25-100 mmol/L)和不同浸涂时间(1-30分钟)下进行测试，先单独测试，然后联合测试，以检查其对表面保护的协同效应。如果单独使用，两者的缓蚀效果都不显著，在所有浓度和浸涂次数下的缓蚀效率都低于50%。相比之下，化合物组合显示出与较高浓度相关的更好的腐蚀抑制作用。在所有方法中，100 mmol/L的化合物组合浓度使重量测试的效率提高了83%，阻抗测量的效率提高了84%，动电位极化的效率提高了91%以上。浸渍涂层变化证明10分钟是所有化合物的最佳选择，化合物组合的最高效率高达86%。
{"title":"N-b-Hydroxyethyl Oleyl Imidazole as Synergist to Enhance the Corrosion Protection Effect of Natural Cocoyl Sarcosine on Steel","authors":"Saad E. Kaskah, Gitta Ehrenhaft, J. Gollnick, C. Fischer","doi":"10.3390/cmd3030029","DOIUrl":"https://doi.org/10.3390/cmd3030029","url":null,"abstract":"To investigate the corrosion protection behavior of naturally derived cocoyl sarcosine in combination with N-b-hydroxyethyl oleyl imidazole for steel CR4 in 0.1 M NaCl, different evaluation systems (weight loss, electrochemical measurements, and spray corrosion tests) were used. Both compounds were tested in different concentrations (25–100 mmol/L) and with variable dip coating times (1–30 min), first individually and then in combination, to check any synergistic effects for surface protection. Both showed only an insignificant corrosion inhibiting effect with less than 50% efficiency at all concentrations and dip coating times if used alone. In contrast, compound combinations revealed an improved corrosion inhibition correlated with higher concentrations. Across all methods, the compound combination concentration of 100 mmol/L resulted in improved efficiency of up to 83% for gravimetric tests, up to 84% for the impedance measure and more than 91% for potentiodynamic polarization. Dip coating variations proved 10 min to be the best option for all compounds with a maximum efficiency of up to 86% for the compound combination.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82557381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A critical review is presented on modeling of the radiolysis of the coolant water in nuclear power reactors with emphasis on ITER. The review is presented in two parts: In Part I, we assess previous work in terms of compliance with important chemical principles and conclude that no model proposed to date is completely satisfactory, in this regard. Thus, some reactions that have been proposed in various radiolysis models are not elementary in nature and can be decomposed into two or more elementary reactions, some of which are already included in the models. These reactions must be removed in formulating a viable model. Furthermore, elementary reactions between species of like charge are also commonly included, but they can be discounted upon the basis of Coulombic repulsion under the prevailing conditions (T < 350 °C) and must also be removed. Likewise, it is concluded that the current state of knowledge with respect to radiolytic yields (i.e., G-values) is also unsatisfactory. More work is required to ensure that the yields used in radiolysis models are truly “primary” yields corresponding to a time scale of nanoseconds or less. This is necessary to ensure that the impact of the reactions that occur outside of the spurs (ionizing particle tracks in the medium) are not counted twice. In Part II, the authors review the use of the radiolysis models coupled with electrochemical models to predict the water chemistry, corrosion potential, crack growth rate in Type 304 SS, and accumulated damage in the coolant circuits of boiling water reactors, pressurized water reactors, and the test fusion reactor, ITER. Based on experience with fission reactors, the emphasis should be placed on the control of the electrochemical corrosion potential because it is the parameter that best describes the state of corrosion in coolant circuits.
{"title":"A Critical Review of Radiolysis Issues in Water-Cooled Fission and Fusion Reactors: Part I, Assessment of Radiolysis Models","authors":"D. Macdonald, G. Engelhardt, A. Petrov","doi":"10.3390/cmd3030028","DOIUrl":"https://doi.org/10.3390/cmd3030028","url":null,"abstract":"A critical review is presented on modeling of the radiolysis of the coolant water in nuclear power reactors with emphasis on ITER. The review is presented in two parts: In Part I, we assess previous work in terms of compliance with important chemical principles and conclude that no model proposed to date is completely satisfactory, in this regard. Thus, some reactions that have been proposed in various radiolysis models are not elementary in nature and can be decomposed into two or more elementary reactions, some of which are already included in the models. These reactions must be removed in formulating a viable model. Furthermore, elementary reactions between species of like charge are also commonly included, but they can be discounted upon the basis of Coulombic repulsion under the prevailing conditions (T < 350 °C) and must also be removed. Likewise, it is concluded that the current state of knowledge with respect to radiolytic yields (i.e., G-values) is also unsatisfactory. More work is required to ensure that the yields used in radiolysis models are truly “primary” yields corresponding to a time scale of nanoseconds or less. This is necessary to ensure that the impact of the reactions that occur outside of the spurs (ionizing particle tracks in the medium) are not counted twice. In Part II, the authors review the use of the radiolysis models coupled with electrochemical models to predict the water chemistry, corrosion potential, crack growth rate in Type 304 SS, and accumulated damage in the coolant circuits of boiling water reactors, pressurized water reactors, and the test fusion reactor, ITER. Based on experience with fission reactors, the emphasis should be placed on the control of the electrochemical corrosion potential because it is the parameter that best describes the state of corrosion in coolant circuits.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76512390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon steel rebar (ASTM A615) has been widely used in reinforced concrete (RC), but its susceptibility to chloride ions remains a critical issue. Low alloy chromium steel has been used to increase corrosion resistance and extend service life, such as in 9% Cr rebar (ASTM A1035-CS). In this work, we characterized two electrochemical systems over time: ASTM A615 and A1035-CS corrugated rebar immersed in SCPS in the presence of NaCl for 12 months. The interfacial processes evolution for the ASTM A1035-CS rebar for both general and local corrosion showed different active-passive responses from those of carbon steel. Because the 3.5% wt. NaCl exceeded the chloride threshold for passive breakdown of both materials, the ASTM A1035-CS showed a five-fold higher impedance and lower general corrosion rate. In localized conditions, the low alloy chrome content rebar showed less density localized attack than the ASTM A615 rebar. These results were attributed to the overall damage evolution involving the formation and stability of corrosion products over time. The local attack appeared to be a random spatial process due to changes in the local environment.
{"title":"Electrochemical Evolution of Carbon Steel and Fe-9% Cr Steel Rebar in Simulated Concrete Pore Solution (SCPS) in the Presence of 3.5 wt% NaCl","authors":"Yi Lu, D. Narayanan, Ryan Brooks, H. Castaneda","doi":"10.3390/cmd3030027","DOIUrl":"https://doi.org/10.3390/cmd3030027","url":null,"abstract":"Carbon steel rebar (ASTM A615) has been widely used in reinforced concrete (RC), but its susceptibility to chloride ions remains a critical issue. Low alloy chromium steel has been used to increase corrosion resistance and extend service life, such as in 9% Cr rebar (ASTM A1035-CS). In this work, we characterized two electrochemical systems over time: ASTM A615 and A1035-CS corrugated rebar immersed in SCPS in the presence of NaCl for 12 months. The interfacial processes evolution for the ASTM A1035-CS rebar for both general and local corrosion showed different active-passive responses from those of carbon steel. Because the 3.5% wt. NaCl exceeded the chloride threshold for passive breakdown of both materials, the ASTM A1035-CS showed a five-fold higher impedance and lower general corrosion rate. In localized conditions, the low alloy chrome content rebar showed less density localized attack than the ASTM A615 rebar. These results were attributed to the overall damage evolution involving the formation and stability of corrosion products over time. The local attack appeared to be a random spatial process due to changes in the local environment.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76442790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cathodic protection efficiency of complex carbon steel structures in confined seawater environment was studied using a specific experimental device. Schematically, this device consisted of a Plexiglas matrix, crossed by a channel 50 cm long, 5 mm deep, 1.5 to 5 cm wide, which moreover included four bends at 90°. Seawater flowed continuously inside the channel over 12 steel coupons embedded in the Plexiglas matrix. Cathodic protection was applied at a constant potential of −1060 mV vs. Ag/AgCl-seawater with respect to a reference electrode located outside the channel, at the seawater flow entry. The potential of four selected coupons was monitored over time via a microelectrode set close to each coupon. It varied significantly with the distance separating the coupons from the channel entry. At the end of the 3.5-month experiment, a polarization curve was acquired. The residual corrosion rate under cathodic protection was estimated via the extrapolation of the anodic Tafel line. It varied from <1 µm yr−1 to 16 µm yr−1, depending on the potential reached by the coupon (between −900 and −1040 mV vs. Ag/AgCl-seawater) at the end of the experiment and on the properties of the calcareous deposit formed on the steel surface.
采用专用实验装置研究了复杂碳钢结构在密闭海水环境中的阴极保护效率。从原理上讲，该装置由有机玻璃基质组成，由一个长50厘米、深5毫米、宽1.5至5厘米的通道交叉，其中还包括四个90°弯曲。海水通过嵌入在有机玻璃基体中的12根钢板在通道内连续流动。在- 1060 mV vs. Ag/ agcl -海水的恒定电位下，对位于通道外的参考电极进行阴极保护。通过靠近每个电极的微电极，监测四个选定电极的电位。它随票券与通道入口之间的距离而显著变化。在3.5个月的实验结束时，获得了偏振曲线。通过外推阳极Tafel线估算了阴极保护下的残余腐蚀速率。它的变化范围从<1 μ m yr - 1到16 μ m yr - 1，这取决于实验结束时电极达到的电势(相对于Ag/ agcl -海水在- 900和- 1040 mV之间)以及钢表面形成的钙质沉积物的性质。
{"title":"Cathodic Protection of Complex Carbon Steel Structures in Seawater","authors":"P. Refait, A. Grolleau, M. Jeannin, R. Sabot","doi":"10.3390/cmd3030026","DOIUrl":"https://doi.org/10.3390/cmd3030026","url":null,"abstract":"Cathodic protection efficiency of complex carbon steel structures in confined seawater environment was studied using a specific experimental device. Schematically, this device consisted of a Plexiglas matrix, crossed by a channel 50 cm long, 5 mm deep, 1.5 to 5 cm wide, which moreover included four bends at 90°. Seawater flowed continuously inside the channel over 12 steel coupons embedded in the Plexiglas matrix. Cathodic protection was applied at a constant potential of −1060 mV vs. Ag/AgCl-seawater with respect to a reference electrode located outside the channel, at the seawater flow entry. The potential of four selected coupons was monitored over time via a microelectrode set close to each coupon. It varied significantly with the distance separating the coupons from the channel entry. At the end of the 3.5-month experiment, a polarization curve was acquired. The residual corrosion rate under cathodic protection was estimated via the extrapolation of the anodic Tafel line. It varied from <1 µm yr−1 to 16 µm yr−1, depending on the potential reached by the coupon (between −900 and −1040 mV vs. Ag/AgCl-seawater) at the end of the experiment and on the properties of the calcareous deposit formed on the steel surface.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76313835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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