We studied the effect of isothermal annealing (600–750 °C, 1 to 1000 min) on the microstructure and mechanical properties of SAF 2205 duplex stainless steel. Impact toughness was found to be significantly more affected than hardness by annealing. Annealing at 750 °C for 1000 min resulted in a more than 90% decrease in impact toughness, while hardness only increased by 25%. Tensile strength increased up to 100 MPa, but elongation decreased by more than 50% under the same conditions. Sigma phase formation was minimal at lower temperatures (650 °C and below) but increased significantly at higher temperatures. At 750 °C and 1000 min of annealing, the ferrite content dropped from 50% to 16%. These findings suggest that annealing temperature and time need to be carefully controlled to avoid a reduction in impact toughness and ductility caused by sigma phase precipitation. The harmful effect of sigma phase precipitation on mechanical properties was directly shown.
我们研究了等温退火（600-750 °C，1 至 1000 分钟）对 SAF 2205 双相不锈钢微观结构和机械性能的影响。研究发现，退火对冲击韧性的影响明显大于对硬度的影响。750 °C 退火 1000 分钟导致冲击韧性下降超过 90%，而硬度仅增加 25%。在相同条件下，拉伸强度增加到 100 兆帕，但伸长率下降了 50%以上。在较低温度（650 °C及以下）下，西格玛相的形成极少，但在较高温度下，西格玛相的形成显著增加。在 750 °C 和 1000 分钟退火条件下，铁素体含量从 50% 降至 16%。这些发现表明，需要仔细控制退火温度和时间，以避免σ相析出导致冲击韧性和延展性降低。直接显示了σ相析出对机械性能的有害影响。
{"title":"Influence of Isothermal Annealing in the 600 to 750 °C Range on the Degradation of SAF 2205 Duplex Stainless Steel","authors":"J. Burja, B. Žužek, B. Šetina Batič","doi":"10.3390/cmd5030014","DOIUrl":"https://doi.org/10.3390/cmd5030014","url":null,"abstract":"We studied the effect of isothermal annealing (600–750 °C, 1 to 1000 min) on the microstructure and mechanical properties of SAF 2205 duplex stainless steel. Impact toughness was found to be significantly more affected than hardness by annealing. Annealing at 750 °C for 1000 min resulted in a more than 90% decrease in impact toughness, while hardness only increased by 25%. Tensile strength increased up to 100 MPa, but elongation decreased by more than 50% under the same conditions. Sigma phase formation was minimal at lower temperatures (650 °C and below) but increased significantly at higher temperatures. At 750 °C and 1000 min of annealing, the ferrite content dropped from 50% to 16%. These findings suggest that annealing temperature and time need to be carefully controlled to avoid a reduction in impact toughness and ductility caused by sigma phase precipitation. The harmful effect of sigma phase precipitation on mechanical properties was directly shown.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"32 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141654909","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}
H. Torbati-Sarraf, Ling Ding, Iman Khakpour, Gisoo Daviran, A. Poursaee
This paper addresses the interplay between electrical fields in the human body and the corrosion behavior of Ti-6Al-4V alloy, a prevalent orthopedic material. The study investigates the impact of alternative electrical signals at different frequencies on the alloy’s electrochemical behavior in a simulated body environment. The human body always has natural sinusoidal potential due to, e.g., heart palpitations and brain/nervous system activities. Ignoring such natural activities may lead to underestimating the corrosion performance of the Ti-6Al-4V alloy in the body. By analyzing anodic and cathodic responses and the net faradaic current induced by alternating current potential, the research sheds light on the influence of electrical fields on corrosion rates. Understanding these dynamics could lead to improved implant materials, mitigating corrosion-related challenges and enhancing implant performance over the long term. Results of this work indicated that frequent oxidation and reduction at certain frequencies may induce corrosion and hinder biomimetic apatite formation, impacting osseointegration. Natural alternative currents in the body affect the corrosion performance of Ti-based implant alloys, highlighting the need for consideration in biomedical applications.
{"title":"Unraveling the Corrosion of the Ti–6Al–4V Orthopedic Alloy in Phosphate-Buffered Saline (PBS) Solution: Influence of Frequency and Potential","authors":"H. Torbati-Sarraf, Ling Ding, Iman Khakpour, Gisoo Daviran, A. Poursaee","doi":"10.3390/cmd5020012","DOIUrl":"https://doi.org/10.3390/cmd5020012","url":null,"abstract":"This paper addresses the interplay between electrical fields in the human body and the corrosion behavior of Ti-6Al-4V alloy, a prevalent orthopedic material. The study investigates the impact of alternative electrical signals at different frequencies on the alloy’s electrochemical behavior in a simulated body environment. The human body always has natural sinusoidal potential due to, e.g., heart palpitations and brain/nervous system activities. Ignoring such natural activities may lead to underestimating the corrosion performance of the Ti-6Al-4V alloy in the body. By analyzing anodic and cathodic responses and the net faradaic current induced by alternating current potential, the research sheds light on the influence of electrical fields on corrosion rates. Understanding these dynamics could lead to improved implant materials, mitigating corrosion-related challenges and enhancing implant performance over the long term. Results of this work indicated that frequent oxidation and reduction at certain frequencies may induce corrosion and hinder biomimetic apatite formation, impacting osseointegration. Natural alternative currents in the body affect the corrosion performance of Ti-based implant alloys, highlighting the need for consideration in biomedical applications.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"5 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141120458","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}
Igor A. Chaves, Peter J. Richardson, Sam Lynch, Jessica A. Allen
With escalating global regulatory pressure for countries to adhere to emission laws, repurposing existing natural gas pipelines for hydrogen-based commodities stands to be an economical solution. However, the effects of hydrogen embrittlement must be thoroughly considered for this application to avoid the unexpected catastrophic failure of these pipelines. The literature proposes several physicochemical embrittlement models. This paper reports one aspect of hydrogen embrittlement that remains to be quantified: the recovery of ductility (embrittlement) of mild steel specimens subjected to artificially accelerated hydrogen absorption via electrochemical charging as a function of time. The effects of charging duration and particularly the delay period between charging and mechanical tensile testing were investigated. Unsurprisingly, longer charging time shows a greater loss of elongation; however, a more extensive recovery of ductility correlated with longer charging time in the first few days after charging. The data also show that while the uncharged mild steel met all minimum required values for strength and elongation for the specified grade, there was a substantial variability in the elongation to failure. The same trends in variability of elongation translated to the hydrogen-charged specimens. Due to this extensive variability, failure to meet the elongation specification of the grade is reported based on the worst-case scenario obtained for a given set of samples for each exposure condition. These results have practical implications for the monitoring and testing of infrastructure exposed to hydrogen, particularly as this relates to industry planned operational shutdown schedules.
{"title":"Impact of the Delay Period between Electrochemical Hydrogen Charging and Tensile Testing on the Mechanical Properties of Mild Steel","authors":"Igor A. Chaves, Peter J. Richardson, Sam Lynch, Jessica A. Allen","doi":"10.3390/cmd5020011","DOIUrl":"https://doi.org/10.3390/cmd5020011","url":null,"abstract":"With escalating global regulatory pressure for countries to adhere to emission laws, repurposing existing natural gas pipelines for hydrogen-based commodities stands to be an economical solution. However, the effects of hydrogen embrittlement must be thoroughly considered for this application to avoid the unexpected catastrophic failure of these pipelines. The literature proposes several physicochemical embrittlement models. This paper reports one aspect of hydrogen embrittlement that remains to be quantified: the recovery of ductility (embrittlement) of mild steel specimens subjected to artificially accelerated hydrogen absorption via electrochemical charging as a function of time. The effects of charging duration and particularly the delay period between charging and mechanical tensile testing were investigated. Unsurprisingly, longer charging time shows a greater loss of elongation; however, a more extensive recovery of ductility correlated with longer charging time in the first few days after charging. The data also show that while the uncharged mild steel met all minimum required values for strength and elongation for the specified grade, there was a substantial variability in the elongation to failure. The same trends in variability of elongation translated to the hydrogen-charged specimens. Due to this extensive variability, failure to meet the elongation specification of the grade is reported based on the worst-case scenario obtained for a given set of samples for each exposure condition. These results have practical implications for the monitoring and testing of infrastructure exposed to hydrogen, particularly as this relates to industry planned operational shutdown schedules.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"2 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140962880","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}
Zahed Ghelichkhah, Digby D. Macdonald, Gregory S. Ferguson
An impedance model based on the Volmer–Heyrovsky–Tafel mechanism was developed to study the kinetics of the hydrogen evolution reaction on polycrystalline gold electrodes at moderate overpotentials in aqueous H2SO4 (0.5 and 1.0 M) solutions. The model was optimized on data from potentiodynamic polarization and electrochemical impedance spectroscopy, and model parameters were extracted. Consistent with expectations, the magnitude of the impedance data indicated a higher rate of hydrogen evolution at lower pH. Also, the fractional surface coverage of adsorbed hydrogen (θHads) increases with increasing overpotential but the small value of θHads indicates only weak adsorption of H on gold. Tafel slopes and exchange current densities were estimated to be in the range of 81–124 mV/dec, and 10−6 and 10−5 A/cm2 in H2SO4 (0.5 and 1.0 M), respectively. The results show that the model accounts well for the experimental data, such as the steady-state current density. Sensitivity analysis reveals that the electrochemical parameters (α1, α2, k10, k−10, and k20) associated with the kinetics of the hydrogen evolution reaction have a major impact on the calculated impedance but the standard rate constant for hydrogen oxidation reaction (k−20) does not strongly affect the calculated impedance.
{"title":"Mechanistic Analysis of Hydrogen Evolution Reaction on Stationary Polycrystalline Gold Electrodes in H2SO4 Solutions","authors":"Zahed Ghelichkhah, Digby D. Macdonald, Gregory S. Ferguson","doi":"10.3390/cmd5020010","DOIUrl":"https://doi.org/10.3390/cmd5020010","url":null,"abstract":"An impedance model based on the Volmer–Heyrovsky–Tafel mechanism was developed to study the kinetics of the hydrogen evolution reaction on polycrystalline gold electrodes at moderate overpotentials in aqueous H2SO4 (0.5 and 1.0 M) solutions. The model was optimized on data from potentiodynamic polarization and electrochemical impedance spectroscopy, and model parameters were extracted. Consistent with expectations, the magnitude of the impedance data indicated a higher rate of hydrogen evolution at lower pH. Also, the fractional surface coverage of adsorbed hydrogen (θHads) increases with increasing overpotential but the small value of θHads indicates only weak adsorption of H on gold. Tafel slopes and exchange current densities were estimated to be in the range of 81–124 mV/dec, and 10−6 and 10−5 A/cm2 in H2SO4 (0.5 and 1.0 M), respectively. The results show that the model accounts well for the experimental data, such as the steady-state current density. Sensitivity analysis reveals that the electrochemical parameters (α1, α2, k10, k−10, and k20) associated with the kinetics of the hydrogen evolution reaction have a major impact on the calculated impedance but the standard rate constant for hydrogen oxidation reaction (k−20) does not strongly affect the calculated impedance.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":" 36","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993147","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}
Julian Cremer, Sinan Kiremit, Heinz Jürgen Klarhorst, Alix Gaspard, Karsten Rasim, T. Kordisch, Andreas Hütten, Dario Anselmetti
Corrosion inhibitors are one of the best practices to prevent the far-reaching negative impacts of corrosion on ferrous alloys. A thorough understanding of their corrosion-inhibiting effects is essential for a sustainable economy and environment. Anionic surfactants are known to act efficiently as corrosion inhibitors. Here, we present that in-situ atomic force microscopy (AFM) measurements can provide deep insights into the adsorption and inhibition mechanism of surfactants on stainless steel surfaces during local corrosion. These include the configuration of surfactant molecules on the surface and how the microstructure of the stainless steel surface influences the inhibition process. Three different anionic surfactants, namely palm kernel oil (PKO), linear alkylbenzene sulfonate (LAS), and fatty alcohol ether sulfate (FAES), were investigated on a titanium-stabilized ferritic stainless steel (1.4510) in NaCl solution. For PKO, the results show random adsorption of bi- and multilayer whereas LAS and FAES adsorb only as local corrosion occurs. Thereby, LAS accumulates only locally and especially at the titanium precipitates of the 1.4510 and FAES forms a densely packed monolayer on the surface. This leads to better corrosion inhibiting properties for LAS and FAES compared to PKO.
{"title":"In-Situ AFM Studies of Surfactant Adsorption on Stainless Steel Surfaces during Electrochemical Polarization","authors":"Julian Cremer, Sinan Kiremit, Heinz Jürgen Klarhorst, Alix Gaspard, Karsten Rasim, T. Kordisch, Andreas Hütten, Dario Anselmetti","doi":"10.3390/cmd5020009","DOIUrl":"https://doi.org/10.3390/cmd5020009","url":null,"abstract":"Corrosion inhibitors are one of the best practices to prevent the far-reaching negative impacts of corrosion on ferrous alloys. A thorough understanding of their corrosion-inhibiting effects is essential for a sustainable economy and environment. Anionic surfactants are known to act efficiently as corrosion inhibitors. Here, we present that in-situ atomic force microscopy (AFM) measurements can provide deep insights into the adsorption and inhibition mechanism of surfactants on stainless steel surfaces during local corrosion. These include the configuration of surfactant molecules on the surface and how the microstructure of the stainless steel surface influences the inhibition process. Three different anionic surfactants, namely palm kernel oil (PKO), linear alkylbenzene sulfonate (LAS), and fatty alcohol ether sulfate (FAES), were investigated on a titanium-stabilized ferritic stainless steel (1.4510) in NaCl solution. For PKO, the results show random adsorption of bi- and multilayer whereas LAS and FAES adsorb only as local corrosion occurs. Thereby, LAS accumulates only locally and especially at the titanium precipitates of the 1.4510 and FAES forms a densely packed monolayer on the surface. This leads to better corrosion inhibiting properties for LAS and FAES compared to PKO.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"8 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140732835","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}
Hydrogen embrittlement (HE) of steel pipelines in high-pressure gaseous environments is a potential threat to the pipeline integrity. The occurrence of gaseous HE is subjected to associative adsorption of hydrogen molecules (H2) at specific “active sites”, such as grain boundaries and dislocations on the steel surface, to generate hydrogen atoms (H). Non-metallic inclusions are another type of metallurgical defect potentially serving as “active sites” to cause the dissociative adsorption of H2. Al2O3 is a common inclusion contained in pipeline steels. In this work, the dissociative adsorption of hydrogen at the α-Al2O3(0001)/α-Fe(111) interface on the Fe011¯ plane was studied by density functional theory calculations. The impact of gas components of O2 and CH4 on the dissociative adsorption of hydrogen was determined. The occurrence of dissociative adsorption of hydrogen at the Al2O3 inclusion/Fe interface is favored under conditions relevant to pipeline operation. Thermodynamic feasibility was observed for Fe and O atoms, but not for Al atoms. H atoms can form more stable adsorption configurations on the Fe side of the interface, while it is less likely for H atoms to adsorb on the Al2O3 side. There is a greater tendency for the occurrence of dissociative adsorption of O2 and CH4 than of H2, due to the more favorable energetics of the former. In particular, the dissociative adsorption of O2 is preferential over that of CH4. The Al-terminated interface exhibits a higher H binding energy compared to the O-terminated interface, indicating a preference for hydrogen accumulation at the Al-terminated interface.
钢制管道在高压气体环境中的氢脆（HE）是对管道完整性的潜在威胁。发生气态 HE 的原因是氢分子 (H2) 在特定的 "活性位点"（如钢表面的晶界和位错）发生关联吸附，生成氢原子 (H)。非金属夹杂物是另一种可能作为 "活性位点 "的冶金缺陷，可导致 H2 的离解吸附。Al2O3 是管道钢中常见的夹杂物。本研究通过密度泛函理论计算研究了氢在 Fe011¯平面上的α-Al2O3(0001)/α-Fe(111)界面上的离解吸附。确定了 O2 和 CH4 气体成分对氢的离解吸附的影响。在与管道运行相关的条件下，Al2O3 包裹体/Fe 界面有利于发生氢的离解吸附。铁原子和 O 原子具有热力学可行性，而铝原子则没有。氢原子可在界面的铁一侧形成更稳定的吸附构型，而氢原子则不太可能吸附在 Al2O3 一侧。与 H2 相比，O2 和 CH4 更倾向于发生离解吸附，这是因为前者的能量更有利。特别是，O2 的解离吸附比 CH4 的解离吸附更有利。与 O 端界面相比，Al 端界面的氢结合能更高，这表明氢更倾向于在 Al 端界面积聚。
{"title":"Dissociative Adsorption of Hydrogen Molecules at Al2O3 Inclusions in Steels and Its Implications for Gaseous Hydrogen Embrittlement of Pipelines","authors":"Yinghao Sun, Frank Cheng","doi":"10.3390/cmd5020008","DOIUrl":"https://doi.org/10.3390/cmd5020008","url":null,"abstract":"Hydrogen embrittlement (HE) of steel pipelines in high-pressure gaseous environments is a potential threat to the pipeline integrity. The occurrence of gaseous HE is subjected to associative adsorption of hydrogen molecules (H2) at specific “active sites”, such as grain boundaries and dislocations on the steel surface, to generate hydrogen atoms (H). Non-metallic inclusions are another type of metallurgical defect potentially serving as “active sites” to cause the dissociative adsorption of H2. Al2O3 is a common inclusion contained in pipeline steels. In this work, the dissociative adsorption of hydrogen at the α-Al2O3(0001)/α-Fe(111) interface on the Fe011¯ plane was studied by density functional theory calculations. The impact of gas components of O2 and CH4 on the dissociative adsorption of hydrogen was determined. The occurrence of dissociative adsorption of hydrogen at the Al2O3 inclusion/Fe interface is favored under conditions relevant to pipeline operation. Thermodynamic feasibility was observed for Fe and O atoms, but not for Al atoms. H atoms can form more stable adsorption configurations on the Fe side of the interface, while it is less likely for H atoms to adsorb on the Al2O3 side. There is a greater tendency for the occurrence of dissociative adsorption of O2 and CH4 than of H2, due to the more favorable energetics of the former. In particular, the dissociative adsorption of O2 is preferential over that of CH4. The Al-terminated interface exhibits a higher H binding energy compared to the O-terminated interface, indicating a preference for hydrogen accumulation at the Al-terminated interface.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"99 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140754279","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}
Fraser King, Miroslav Kolàř, S. Briggs, M. Behazin, P. Keech, N. Diomidis
The disposal of high-level radioactive waste (HLW) and spent nuclear fuel (SF) presents a unique challenge for the prediction of the long-term performance of corrodible structures since HLW/SF containers are expected, in some cases, to have lifetimes of one million years or longer. Various empirical and deterministic models have been developed over the past 45 years for making predictions of long-term corrosion behaviour, including models for uniform and localised corrosion, environmentally assisted cracking, microbiologically influenced corrosion, and radiation-induced corrosion. More recently, fracture-mechanics-based approaches have been developed to account for joint mechanical–corrosion degradation modes. Regardless of whether empirical or deterministic models are used, it is essential to be able to demonstrate a thorough mechanistic understanding of the corrosion processes involved. In addition to process models focused on specific corrosion mechanisms, there is also a need for performance-assessment models as part of the overall demonstration of the safety of a deep geological repository. Performance-assessment models are discussed in Part 2 of this review.
{"title":"Review of the Modelling of Corrosion Processes and Lifetime Prediction for HLW/SF Containers—Part 1: Process Models","authors":"Fraser King, Miroslav Kolàř, S. Briggs, M. Behazin, P. Keech, N. Diomidis","doi":"10.3390/cmd5020007","DOIUrl":"https://doi.org/10.3390/cmd5020007","url":null,"abstract":"The disposal of high-level radioactive waste (HLW) and spent nuclear fuel (SF) presents a unique challenge for the prediction of the long-term performance of corrodible structures since HLW/SF containers are expected, in some cases, to have lifetimes of one million years or longer. Various empirical and deterministic models have been developed over the past 45 years for making predictions of long-term corrosion behaviour, including models for uniform and localised corrosion, environmentally assisted cracking, microbiologically influenced corrosion, and radiation-induced corrosion. More recently, fracture-mechanics-based approaches have been developed to account for joint mechanical–corrosion degradation modes. Regardless of whether empirical or deterministic models are used, it is essential to be able to demonstrate a thorough mechanistic understanding of the corrosion processes involved. In addition to process models focused on specific corrosion mechanisms, there is also a need for performance-assessment models as part of the overall demonstration of the safety of a deep geological repository. Performance-assessment models are discussed in Part 2 of this review.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"121 40","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140370333","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}
Haozheng J. Qu, Liang Yin, Michael Larsen, R. B. Rebak
The corrosion-resistant properties of IronChromium–Aluminum (FeCrAl) alloys have been known for nearly a century. Since the 1950s, they have been explored for application in the generation of nuclear power. In the last decade, the focus has been on the use of FeCrAl as cladding for uranium dioxide fuel in light water reactors (LWRs). The corrosion resistance of this alloy depends on the oxide that it can develop on the surface. In LWRs in the vicinity of 300 °C, the external surface oxide of the FeCrAl cladding could be rich in Fe under oxidizing conditions but rich in Cr under reducing conditions. If there is an accident and the cladding is exposed to superheated steam, the cladding will protect itself by developing an alpha aluminum film on the surface.
铁铬铝合金（FeCrAl）的耐腐蚀性能在近一个世纪前就已为人所知。自 20 世纪 50 年代以来，人们一直在探索将它们应用于核能发电。在过去的十年中，重点是将铁铬铝用作轻水反应堆（LWR）中二氧化铀燃料的包壳。这种合金的耐腐蚀性取决于其表面可能形成的氧化物。在 300 °C 附近的轻水反应堆中，铁铬铝包层的外表面氧化物在氧化条件下可能富含铁，而在还原条件下则富含铬。如果发生事故，堆芯暴露在过热蒸汽中，堆芯将通过在表面形成一层α铝膜来保护自己。
{"title":"Distinctive Oxide Films Develop on the Surface of FeCrAl as the Environment Changes for Nuclear Fuel Cladding","authors":"Haozheng J. Qu, Liang Yin, Michael Larsen, R. B. Rebak","doi":"10.3390/cmd5010006","DOIUrl":"https://doi.org/10.3390/cmd5010006","url":null,"abstract":"The corrosion-resistant properties of IronChromium–Aluminum (FeCrAl) alloys have been known for nearly a century. Since the 1950s, they have been explored for application in the generation of nuclear power. In the last decade, the focus has been on the use of FeCrAl as cladding for uranium dioxide fuel in light water reactors (LWRs). The corrosion resistance of this alloy depends on the oxide that it can develop on the surface. In LWRs in the vicinity of 300 °C, the external surface oxide of the FeCrAl cladding could be rich in Fe under oxidizing conditions but rich in Cr under reducing conditions. If there is an accident and the cladding is exposed to superheated steam, the cladding will protect itself by developing an alpha aluminum film on the surface.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"41 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140232513","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}
Saleh Ahmed, Katerina Lepkova, Xiao Sun, William D. A. Rickard, T. Pojtanabuntoeng
Phenolic-epoxy coatings, which are designed to protect substrates from thermal damage, are widely applied in many fields. There remains an inadequate understanding of how such coatings change during their service life after exposure to various temperature conditions. To further elucidate this issue, this case study investigated the effects of high temperatures on carbon steel panels coated with phenolic epoxy and exposed to different heating conditions. A general trend of decreasing barrier performance was observed after exposure to 150 °C for 3 d, as evidenced by the appearance of cracks on the panel surfaces. In contrast, the coating performance improved after exposure to isothermal conditions (120 °C) or thermal cycling from room temperature to 120 °C, as indicated by the increased low-frequency impedance modulus values of the coating. This unexpected improvement was further examined by characterising the coatings using transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), pull-off adhesion tests, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The maximum pull-off adhesion force (24.9 ± 3.6 MPa) was measured after thermal cycling for 40 d.
酚醛环氧涂料旨在保护基材免受热损伤，被广泛应用于许多领域。但人们对此类涂层在暴露于各种温度条件下的使用寿命期间如何变化仍缺乏足够的了解。为了进一步阐明这一问题，本案例研究调查了高温对涂有酚醛环氧树脂并暴露在不同加热条件下的碳钢面板的影响。在 150 °C 下暴露 3 d 后，观察到阻隔性能总体呈下降趋势，面板表面出现裂纹就是证明。相反，在等温条件下（120 °C）或从室温到 120 °C的热循环条件下，涂层性能有所改善，这体现在涂层的低频阻抗模量值有所增加。通过使用变换红外光谱法（FTIR）、热重分析法（TGA）、差示扫描量热法（DSC）、拉脱附着力测试和飞行时间二次离子质谱法（ToF-SIMS）对涂层进行表征，进一步检验了这一意想不到的改进。热循环 40 d 后，测得最大拉脱附着力（24.9 ± 3.6 兆帕）。
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Corrosion on the interface between a metal alloy, such as steel, and a wet, permeable non-metallic medium is of considerable practical interest. Examples include the interface between steel and water, the atmosphere or concrete, as for steel reinforcement bars; between metal and soil, as for buried cast iron or steel pipes; deposits of some type, as in under-deposit corrosion; and the interface with insulation, protective coatings, or macro- or micro-biological agents. In all cases, corrosion initiation depends on the characteristics of the interfacial zone, both of the metal and the medium, and the spatial variability. For (near-)homogeneous semi-infinite media with good interfacial contact, the pitting, crevices and general corrosion of the metal will be largely controlled by the metal (micro-)characteristics, including its inclusions, imperfections and surface roughness. In other cases, these may be overshadowed by the macro-characteristics of the medium and the degree of interfacial contact, possibly with severe resulting corrosion. Where the build-up of corrosion products can occur at the interface, they will dominate longer-term corrosion and govern the long-term corrosion rate. For media of finite thickness, diffusion issues and material deterioration may also be involved. The practical implications are outlined. It is argued that with the presence of a suitable medium, it is possible to achieve negligible long-term corrosion but only if certain practical actions are taken.
{"title":"Corrosion at the Steel–Medium Interface","authors":"R. Melchers","doi":"10.3390/cmd5010003","DOIUrl":"https://doi.org/10.3390/cmd5010003","url":null,"abstract":"Corrosion on the interface between a metal alloy, such as steel, and a wet, permeable non-metallic medium is of considerable practical interest. Examples include the interface between steel and water, the atmosphere or concrete, as for steel reinforcement bars; between metal and soil, as for buried cast iron or steel pipes; deposits of some type, as in under-deposit corrosion; and the interface with insulation, protective coatings, or macro- or micro-biological agents. In all cases, corrosion initiation depends on the characteristics of the interfacial zone, both of the metal and the medium, and the spatial variability. For (near-)homogeneous semi-infinite media with good interfacial contact, the pitting, crevices and general corrosion of the metal will be largely controlled by the metal (micro-)characteristics, including its inclusions, imperfections and surface roughness. In other cases, these may be overshadowed by the macro-characteristics of the medium and the degree of interfacial contact, possibly with severe resulting corrosion. Where the build-up of corrosion products can occur at the interface, they will dominate longer-term corrosion and govern the long-term corrosion rate. For media of finite thickness, diffusion issues and material deterioration may also be involved. The practical implications are outlined. It is argued that with the presence of a suitable medium, it is possible to achieve negligible long-term corrosion but only if certain practical actions are taken.","PeriodicalId":10693,"journal":{"name":"Corrosion and Materials Degradation","volume":"70 40","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486233","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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