High-entropy alloys (HEAs) have attracted increasing attention owing to their multi-component characteristics with notable high entropy effects. However, obtaining HEAs with improved properties is still challenging. The properties of HEAs can be modulated by the fabrication technique. Electrodeposition could achieve the desired performance characteristics of HEA coatings while operating at reduced processing temperatures and energy consumption levels. Herein, novel FeCoNiCr HEA coatings were electrodeposited on copper substrates under various current densities. The microstructure, coating thickness, hardness, wear resistance, and corrosion properties of the FeCoNiCr HEA coatings prepared at different current densities were all examined. X-ray diffraction (XRD) revealed HEA coatings with a single disordered face-centered cubic (FCC) solid solution phase. Scanning electron microscopy (SEM) indicated uniform and dense surface of FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2, with significantly reduced coating cracking and improved structural integrity. The coatings prepared at 25A/dm2 also exhibited maximum thickness and favorable bonding with the substrate, as well as notably enhanced wear resistance. As the preparation current density increases, the hardness of the coating increases. The hardness of the coating reaches its maximum at 30A/dm2. FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2 in a 3.5 wt% NaCl solution simulated seawater conditions demonstrated improved electrochemical resistance to corrosion. By comparing the microstructure, Elemental content and properties of coatings prepared at various current densities, it was found that the FeCoNiCr high entropy alloy coating prepared at 25A/dm2 showed the best performance.
高熵合金（HEAs）因其多组分特性和显著的高熵效应而受到越来越多的关注。然而，要获得性能更好的高熵合金仍然具有挑战性。HEA 的特性可通过制造技术进行调节。电沉积可以在降低加工温度和能耗水平的同时，实现 HEA 涂层所需的性能特征。本文在不同电流密度下，在铜基底上电沉积了新型铁钴镍铬 HEA 涂层。研究了不同电流密度下制备的铁钴镍铬高压电解镀层的微观结构、镀层厚度、硬度、耐磨性和腐蚀性能。X 射线衍射 (XRD) 显示 HEA 涂层具有单一无序面心立方 (FCC) 固溶相。扫描电子显微镜（SEM）显示，在 25 A/dm2 的电流密度下制备的铁钴镍铬 HEA 涂层表面均匀致密，涂层开裂现象明显减少，结构完整性得到改善。在 25A/dm2 下制备的涂层还显示出最大厚度和与基体的良好结合，以及明显增强的耐磨性。随着制备电流密度的增加，涂层的硬度也在增加。涂层硬度在 30A/dm2 时达到最大值。在模拟海水条件的 3.5 wt% 氯化钠溶液中，以 25 A/dm2 的电流密度制备的铁钴镍铬 HEA 涂层显示出更强的耐腐蚀电化学性能。通过比较在不同电流密度下制备的涂层的微观结构、元素含量和性能，发现在 25A/dm2 下制备的铁钴镍铬高熵合金涂层性能最佳。
{"title":"Microstructures and properties of FeCoNiCr high-entropy alloy coatings prepared by electrodeposition","authors":"Xiang Ju, Chuanbo Zheng, Tianyi Lv, Hongbo Ju, Han Ma, Dianchun Ju, Jiming Zhang, Kaifei Gong, Bowen Li, Xiaotian Wang, Wenkai Zou","doi":"10.5006/4493","DOIUrl":"https://doi.org/10.5006/4493","url":null,"abstract":"\u0000 High-entropy alloys (HEAs) have attracted increasing attention owing to their multi-component characteristics with notable high entropy effects. However, obtaining HEAs with improved properties is still challenging. The properties of HEAs can be modulated by the fabrication technique. Electrodeposition could achieve the desired performance characteristics of HEA coatings while operating at reduced processing temperatures and energy consumption levels. Herein, novel FeCoNiCr HEA coatings were electrodeposited on copper substrates under various current densities. The microstructure, coating thickness, hardness, wear resistance, and corrosion properties of the FeCoNiCr HEA coatings prepared at different current densities were all examined. X-ray diffraction (XRD) revealed HEA coatings with a single disordered face-centered cubic (FCC) solid solution phase. Scanning electron microscopy (SEM) indicated uniform and dense surface of FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2, with significantly reduced coating cracking and improved structural integrity. The coatings prepared at 25A/dm2 also exhibited maximum thickness and favorable bonding with the substrate, as well as notably enhanced wear resistance. As the preparation current density increases, the hardness of the coating increases. The hardness of the coating reaches its maximum at 30A/dm2. FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2 in a 3.5 wt% NaCl solution simulated seawater conditions demonstrated improved electrochemical resistance to corrosion. By comparing the microstructure, Elemental content and properties of coatings prepared at various current densities, it was found that the FeCoNiCr high entropy alloy coating prepared at 25A/dm2 showed the best performance.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139810021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-entropy alloys (HEAs) have attracted increasing attention owing to their multi-component characteristics with notable high entropy effects. However, obtaining HEAs with improved properties is still challenging. The properties of HEAs can be modulated by the fabrication technique. Electrodeposition could achieve the desired performance characteristics of HEA coatings while operating at reduced processing temperatures and energy consumption levels. Herein, novel FeCoNiCr HEA coatings were electrodeposited on copper substrates under various current densities. The microstructure, coating thickness, hardness, wear resistance, and corrosion properties of the FeCoNiCr HEA coatings prepared at different current densities were all examined. X-ray diffraction (XRD) revealed HEA coatings with a single disordered face-centered cubic (FCC) solid solution phase. Scanning electron microscopy (SEM) indicated uniform and dense surface of FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2, with significantly reduced coating cracking and improved structural integrity. The coatings prepared at 25A/dm2 also exhibited maximum thickness and favorable bonding with the substrate, as well as notably enhanced wear resistance. As the preparation current density increases, the hardness of the coating increases. The hardness of the coating reaches its maximum at 30A/dm2. FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2 in a 3.5 wt% NaCl solution simulated seawater conditions demonstrated improved electrochemical resistance to corrosion. By comparing the microstructure, Elemental content and properties of coatings prepared at various current densities, it was found that the FeCoNiCr high entropy alloy coating prepared at 25A/dm2 showed the best performance.
高熵合金（HEAs）因其多组分特性和显著的高熵效应而受到越来越多的关注。然而，要获得性能更好的高熵合金仍然具有挑战性。HEA 的特性可通过制造技术进行调节。电沉积可以在降低加工温度和能耗水平的同时，实现 HEA 涂层所需的性能特征。本文在不同电流密度下，在铜基底上电沉积了新型铁钴镍铬 HEA 涂层。研究了不同电流密度下制备的铁钴镍铬高压电解镀层的微观结构、镀层厚度、硬度、耐磨性和腐蚀性能。X 射线衍射 (XRD) 显示 HEA 涂层具有单一无序面心立方 (FCC) 固溶相。扫描电子显微镜（SEM）显示，在 25 A/dm2 的电流密度下制备的铁钴镍铬 HEA 涂层表面均匀致密，涂层开裂现象明显减少，结构完整性得到改善。在 25A/dm2 下制备的涂层还显示出最大厚度和与基体的良好结合，以及明显增强的耐磨性。随着制备电流密度的增加，涂层的硬度也在增加。涂层硬度在 30A/dm2 时达到最大值。在模拟海水条件的 3.5 wt% 氯化钠溶液中，以 25 A/dm2 的电流密度制备的铁钴镍铬 HEA 涂层显示出更强的耐腐蚀电化学性能。通过比较在不同电流密度下制备的涂层的微观结构、元素含量和性能，发现在 25A/dm2 下制备的铁钴镍铬高熵合金涂层性能最佳。
{"title":"Microstructures and properties of FeCoNiCr high-entropy alloy coatings prepared by electrodeposition","authors":"Xiang Ju, Chuanbo Zheng, Tianyi Lv, Hongbo Ju, Han Ma, Dianchun Ju, Jiming Zhang, Kaifei Gong, Bowen Li, Xiaotian Wang, Wenkai Zou","doi":"10.5006/4493","DOIUrl":"https://doi.org/10.5006/4493","url":null,"abstract":"\u0000 High-entropy alloys (HEAs) have attracted increasing attention owing to their multi-component characteristics with notable high entropy effects. However, obtaining HEAs with improved properties is still challenging. The properties of HEAs can be modulated by the fabrication technique. Electrodeposition could achieve the desired performance characteristics of HEA coatings while operating at reduced processing temperatures and energy consumption levels. Herein, novel FeCoNiCr HEA coatings were electrodeposited on copper substrates under various current densities. The microstructure, coating thickness, hardness, wear resistance, and corrosion properties of the FeCoNiCr HEA coatings prepared at different current densities were all examined. X-ray diffraction (XRD) revealed HEA coatings with a single disordered face-centered cubic (FCC) solid solution phase. Scanning electron microscopy (SEM) indicated uniform and dense surface of FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2, with significantly reduced coating cracking and improved structural integrity. The coatings prepared at 25A/dm2 also exhibited maximum thickness and favorable bonding with the substrate, as well as notably enhanced wear resistance. As the preparation current density increases, the hardness of the coating increases. The hardness of the coating reaches its maximum at 30A/dm2. FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2 in a 3.5 wt% NaCl solution simulated seawater conditions demonstrated improved electrochemical resistance to corrosion. By comparing the microstructure, Elemental content and properties of coatings prepared at various current densities, it was found that the FeCoNiCr high entropy alloy coating prepared at 25A/dm2 showed the best performance.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139870099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hui Su, Jun Wang, Yuxing Zeng, Chenmeng Dang, Yi Xie, Song Xu, Yongli Huang, Zhi Li, Tangqing Wu
Machine learning has been widely applied to exploring the key affecting factors for metal corrosion in some local regions. However, there is a lack of systemic research and practicable prediction model for the metal corrosion in a broad region. In this paper, the corrosion map of Q235 steel in a broad region of acidic soils of Hunan province of Central China was constructed and optimized via the field experiment and machine learning. Both the experimental and optimized corrosion maps confirmed that the corrosion rate of the steel decreased from the western to the eastern part of the province. The concentrations of pH, F−, Cl−, NO3−, HCO3−, K+ and Mg2+ were the key affecting factors in the broad region of acidic soils of the province. Among them, the contribution rate of the HCO3− concentration was higher than that of other factors. The optimization model based on the ordinary least squares could be used for the optimization of the corrosion map of steels a broad region of acidic soils. The optimized corrosion map was a good alternative of the estimation methods for the corrosion rate of steels in soil.
{"title":"Construction and optimization of corrosion map in a broad region of acidic soil via machine learning","authors":"Hui Su, Jun Wang, Yuxing Zeng, Chenmeng Dang, Yi Xie, Song Xu, Yongli Huang, Zhi Li, Tangqing Wu","doi":"10.5006/4498","DOIUrl":"https://doi.org/10.5006/4498","url":null,"abstract":"\u0000 Machine learning has been widely applied to exploring the key affecting factors for metal corrosion in some local regions. However, there is a lack of systemic research and practicable prediction model for the metal corrosion in a broad region. In this paper, the corrosion map of Q235 steel in a broad region of acidic soils of Hunan province of Central China was constructed and optimized via the field experiment and machine learning. Both the experimental and optimized corrosion maps confirmed that the corrosion rate of the steel decreased from the western to the eastern part of the province. The concentrations of pH, F−, Cl−, NO3−, HCO3−, K+ and Mg2+ were the key affecting factors in the broad region of acidic soils of the province. Among them, the contribution rate of the HCO3− concentration was higher than that of other factors. The optimization model based on the ordinary least squares could be used for the optimization of the corrosion map of steels a broad region of acidic soils. The optimized corrosion map was a good alternative of the estimation methods for the corrosion rate of steels in soil.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139599767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Reyad, M. S. Hazarabedian, Yang Hou, E. Hornus, Mariano Iannuzzi
Resistant to aggressive reducing environments and combining excellent mechanical properties, the age-hardenable Alloy 718 is the most broadly used nickel alloy in the oil and gas industry. Nevertheless, its localized corrosion resistance in oxidizing halide-containing environments has yet to be thoroughly investigated, with conflicting results discussed in the literature. In this regard, Alloy 718 has a relatively low pitting resistance equivalent (PRE), limiting in practice its use where localized corrosion is expected, particularly in seawater applications. This work quantified the localized corrosion resistance of the alloy in chloride-containing environments. The potentiodynamic-galvanostatic-potentiodynamic (PD-GS-PD) technique was used to determine the crevice corrosion repassivation potential (ER, CREV) in deaerated natural seawater at different temperatures for two Alloy 718 grades (i.e., aerospace, as per ASTM B670, and oil and gas, as per API 6ACRA, grades). Additionally, potentiodynamic polarization testing was conducted for the API 6ACRA grade in acidified solutions with varying chloride concentrations to simulate pit/crevice-like conditions. In the aerospace heat treatment condition, Alloy 718 suffered crevice corrosion at temperatures as low as 10°C, while the API 6ACRA grade remained unaffected at the same testing temperature. Stable crevice corrosion occurred at 20°C and 50°C for both grades.
可时效硬化的合金 718 可抵抗侵蚀性还原环境，并具有优异的机械性能，是石油和天然气行业中应用最广泛的镍合金。然而，它在含氧化卤环境中的局部耐腐蚀性能仍有待深入研究，文献中讨论的结果相互矛盾。在这方面，合金 718 的抗点蚀当量 (PRE) 相对较低，这限制了它在预计会发生局部腐蚀的地方的实际应用，尤其是在海水应用中。这项研究对合金在含氯环境中的局部耐腐蚀性进行了量化。采用电位动力-静电位（PD-GS-PD）技术确定了两种合金 718 牌号（即航空航天牌号（符合 ASTM B670 标准）和石油天然气牌号（符合 API 6ACRA 标准））在不同温度下脱氧天然海水中的缝隙腐蚀再钝化电位（ER，CREV）。此外，还在不同氯化物浓度的酸化溶液中对 API 6ACRA 牌号进行了电位极化测试，以模拟类似凹坑/裂缝的条件。在航空热处理条件下，合金 718 在低至 10°C 的温度下就会发生缝隙腐蚀，而 API 6ACRA 牌号在相同的测试温度下则不受影响。在 20°C 和 50°C 时，两种牌号都出现了稳定的缝隙腐蚀。
{"title":"Localized Corrosion Resistance of Nickel Alloy 718 In Chloride-Containing Environments","authors":"A. Reyad, M. S. Hazarabedian, Yang Hou, E. Hornus, Mariano Iannuzzi","doi":"10.5006/4459","DOIUrl":"https://doi.org/10.5006/4459","url":null,"abstract":"\u0000 Resistant to aggressive reducing environments and combining excellent mechanical properties, the age-hardenable Alloy 718 is the most broadly used nickel alloy in the oil and gas industry. Nevertheless, its localized corrosion resistance in oxidizing halide-containing environments has yet to be thoroughly investigated, with conflicting results discussed in the literature. In this regard, Alloy 718 has a relatively low pitting resistance equivalent (PRE), limiting in practice its use where localized corrosion is expected, particularly in seawater applications. This work quantified the localized corrosion resistance of the alloy in chloride-containing environments. The potentiodynamic-galvanostatic-potentiodynamic (PD-GS-PD) technique was used to determine the crevice corrosion repassivation potential (ER, CREV) in deaerated natural seawater at different temperatures for two Alloy 718 grades (i.e., aerospace, as per ASTM B670, and oil and gas, as per API 6ACRA, grades). Additionally, potentiodynamic polarization testing was conducted for the API 6ACRA grade in acidified solutions with varying chloride concentrations to simulate pit/crevice-like conditions. In the aerospace heat treatment condition, Alloy 718 suffered crevice corrosion at temperatures as low as 10°C, while the API 6ACRA grade remained unaffected at the same testing temperature. Stable crevice corrosion occurred at 20°C and 50°C for both grades.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139602423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, the use of electrical resistivity (ρ) of concrete as a design parameter has intensified, ranging from its use as a durability index in laboratories for the characterization of cement-based materials, as well as in inspection of existing structures, in order to diagnose the pathological problems they present. It has also being used as a durability index to accept or reject a concrete mixture during the construction of concrete infrastructure that it should comply as a durable concrete mixture. ρ of concrete has also been used as an indirect measure of the corrosion rate (icorr) of the embedded steel in concrete to determine not only the time of corrosion initiation, but also the propagation time of corrosion of reinforcing or prestressing steel. This allows indirect measurements of icorr from ρ measurements on the concrete surface without the need to connect the reinforcing or prestressing steel to the measuring equipment. The present investigation presents some results from the literature that corroborate this direct correlation between ρ of concrete and icorr of the embedded steel for some exposure conditions, and some considerations are discussed to avoid possible measurement interpretation errors if this correlation is used in real structures.
{"title":"Considerations to avoid corrosion rate estimate error of the reinforcing steel if it is based only on concrete’s electrical resistivity.","authors":"A. Torres‐Acosta","doi":"10.5006/4482","DOIUrl":"https://doi.org/10.5006/4482","url":null,"abstract":"\u0000 In recent years, the use of electrical resistivity (ρ) of concrete as a design parameter has intensified, ranging from its use as a durability index in laboratories for the characterization of cement-based materials, as well as in inspection of existing structures, in order to diagnose the pathological problems they present. It has also being used as a durability index to accept or reject a concrete mixture during the construction of concrete infrastructure that it should comply as a durable concrete mixture. ρ of concrete has also been used as an indirect measure of the corrosion rate (icorr) of the embedded steel in concrete to determine not only the time of corrosion initiation, but also the propagation time of corrosion of reinforcing or prestressing steel. This allows indirect measurements of icorr from ρ measurements on the concrete surface without the need to connect the reinforcing or prestressing steel to the measuring equipment. The present investigation presents some results from the literature that corroborate this direct correlation between ρ of concrete and icorr of the embedded steel for some exposure conditions, and some considerations are discussed to avoid possible measurement interpretation errors if this correlation is used in real structures.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139605678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An intact and X-scribed Al-5wt%Zn rich primer (AlRP) without pretreatment or topcoat was evaluated for its ability to suppress potential dependent intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGC-SCC) of peak aged AA7075A-T651 in NaCl salt fog and full immersion. The ability of the primer to provide sacrificial anode-based cathodic prevention of peak aged AA7075-T651 substrate was evaluated both under the primer coating and at scratches. The AlRP evaluated consisted of an epoxy-based resin embedded with spherical Al-5wt%Zn pigment particles. Performance was evaluated under full immersion in 0.6 M NaCl solution and compared to ASTM B-117 salt spray exposure using two approaches. These consisted of the University of Virginia (UVa) cycle test on intact coatings and the full immersion galvanic couple testing on simulated scratched panels created when intact coatings form bimetal couples with bare AA7075-T651. Focus was placed on the ability of the AlRP to achieve a targeted intermediate galvanic couple potential near a “prevention” potential which suppresses stress corrosion crack growth, intermetallic particle corrosion as well as intergranular corrosion. The long term (24-hour) open circuit potential (OCP) of AlRP coated AA7075-T651 in 0.6 M NaCl indicated that the AlRP provided less than 100mV of cathodic potential shift of the intact coating from its OCP. Electrochemical cycle testing conducted at −0.95 VSCE demonstrates that the AlRP did not enable sacrificial anode-based cathodic protection as the coupled potential remained at the corrosion potential of bare AA7075-T651. Furthermore, the current observed throughout galvanic corrosion experiments coupling of AlRP:AA7075-T651 indicated the AlRP coating was a cathode in the bimetal galvanic couple. ASTM B117 salt spray exposure of the AlRP revealed oxidation of the AA 7075-T651 substrate below the primer detected as a continually growing oxygen signal at the primer-substrate interface that did not arrest corrosion over the exposure period.
{"title":"Electrochemical Evaluation of Al-5 wt% Zn Metal Rich Primer for Protection of Al-Zn-Mg-Cu Alloy in NaCl","authors":"A. Korjenic, L. Blohm, A. Druschitz, J. R. Scully","doi":"10.5006/4424","DOIUrl":"https://doi.org/10.5006/4424","url":null,"abstract":"\u0000 An intact and X-scribed Al-5wt%Zn rich primer (AlRP) without pretreatment or topcoat was evaluated for its ability to suppress potential dependent intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGC-SCC) of peak aged AA7075A-T651 in NaCl salt fog and full immersion. The ability of the primer to provide sacrificial anode-based cathodic prevention of peak aged AA7075-T651 substrate was evaluated both under the primer coating and at scratches. The AlRP evaluated consisted of an epoxy-based resin embedded with spherical Al-5wt%Zn pigment particles. Performance was evaluated under full immersion in 0.6 M NaCl solution and compared to ASTM B-117 salt spray exposure using two approaches. These consisted of the University of Virginia (UVa) cycle test on intact coatings and the full immersion galvanic couple testing on simulated scratched panels created when intact coatings form bimetal couples with bare AA7075-T651. Focus was placed on the ability of the AlRP to achieve a targeted intermediate galvanic couple potential near a “prevention” potential which suppresses stress corrosion crack growth, intermetallic particle corrosion as well as intergranular corrosion. The long term (24-hour) open circuit potential (OCP) of AlRP coated AA7075-T651 in 0.6 M NaCl indicated that the AlRP provided less than 100mV of cathodic potential shift of the intact coating from its OCP. Electrochemical cycle testing conducted at −0.95 VSCE demonstrates that the AlRP did not enable sacrificial anode-based cathodic protection as the coupled potential remained at the corrosion potential of bare AA7075-T651. Furthermore, the current observed throughout galvanic corrosion experiments coupling of AlRP:AA7075-T651 indicated the AlRP coating was a cathode in the bimetal galvanic couple. ASTM B117 salt spray exposure of the AlRP revealed oxidation of the AA 7075-T651 substrate below the primer detected as a continually growing oxygen signal at the primer-substrate interface that did not arrest corrosion over the exposure period.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139615867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Zhai, Ferdinan Cintron-Colon, Ryan A. Bouffioux, M. Toloczko
The stress corrosion cracking behavior of high-strength Ni-base Alloy X-750 and Alloy 718 has been investigated to assess the effect of replacing LiOH with KOH as the pH moderator in pressurized water reactor (PWR) primary circuit coolant. The SCC initiation behavior of X-750 was evaluated by multi-tensile specimen constant load test in either LiOH- or KOH- containing PWR primary water. The SCC growth behavior of X-750 and Alloy 718 was evaluated on compact tension specimens with on-the-fly changes between LiOH- and KOH-containing water in three different PWR primary water chemistries. Direct current potential drop technique was used for in-situ monitoring of crack initiation time and crack extension in SCC initiation and propagation tests, respectively. The results suggest no significant effect of KOH vs. LiOH on the SCC initiation or propagation of the tested materials.
{"title":"Stress Corrosion Cracking of High-Strength Ni-Base Alloys in PWR Primary Water Containing KOH vs. LiOH","authors":"Z. Zhai, Ferdinan Cintron-Colon, Ryan A. Bouffioux, M. Toloczko","doi":"10.5006/4460","DOIUrl":"https://doi.org/10.5006/4460","url":null,"abstract":"\u0000 The stress corrosion cracking behavior of high-strength Ni-base Alloy X-750 and Alloy 718 has been investigated to assess the effect of replacing LiOH with KOH as the pH moderator in pressurized water reactor (PWR) primary circuit coolant. The SCC initiation behavior of X-750 was evaluated by multi-tensile specimen constant load test in either LiOH- or KOH- containing PWR primary water. The SCC growth behavior of X-750 and Alloy 718 was evaluated on compact tension specimens with on-the-fly changes between LiOH- and KOH-containing water in three different PWR primary water chemistries. Direct current potential drop technique was used for in-situ monitoring of crack initiation time and crack extension in SCC initiation and propagation tests, respectively. The results suggest no significant effect of KOH vs. LiOH on the SCC initiation or propagation of the tested materials.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139528248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sewer networks are not only necessary as an infrastructure for human societies, but they can also help humans achieve a stable situation with the surrounding natural environment by controlling and preventing the spread of pollution in the environment. As a result, concrete sewer maintenance and analysis of their damaging elements are critical. In this regard, modeling microbiologically influenced corrosion (MIC) is a challenging phenomenon. Due to the complicated aspects related to the interaction of microorganisms and concrete degradation, this research suggests several machine-learning models as well as traditional multiple linear regression (MLR) model to predict the MIC in sewer pipelines. The models can be categorized into three sections: (i) stand-alone models (GMDH, GRNN, RBFNN, MLPNN, CHAID, and CART), (ii) integrative models (ANFIS and SVR with PSO, ABC and FA) and (iii) ensemble meta-learner Stepwise Regression model. After implementing the models, statistical measures, including RMSE, MAE, MBE, PCC, and Nash–Sutcliffe model efficiency (NSE) are considered for evaluating models' performances. The results indicate that the ensemble Meta-learner-SR model is significantly more precise than other models. They also demonstrate that using an integrative model can improve the accuracy of stand-alone models by at least up to 42 percent. The durability and lifespan of the sewer system is also estimated by the aid of the best predictive model (Meta-learner-SR) for two scenario cases of (i) gas phase and (ii) submerged conditions. It is concluded that the sewer systems have a considerably lower life span (24 years less) exposed to submerged sewage than the gas phase with 56 years of durability.
{"title":"Predicting Microbiologically Influenced Concrete Corrosion in Self-cleansing Sewers using Meta-learning Techniques","authors":"Mohammad Zounemat-Kermani, Ammar Aldallal","doi":"10.5006/4457","DOIUrl":"https://doi.org/10.5006/4457","url":null,"abstract":"\u0000 Sewer networks are not only necessary as an infrastructure for human societies, but they can also help humans achieve a stable situation with the surrounding natural environment by controlling and preventing the spread of pollution in the environment. As a result, concrete sewer maintenance and analysis of their damaging elements are critical. In this regard, modeling microbiologically influenced corrosion (MIC) is a challenging phenomenon. Due to the complicated aspects related to the interaction of microorganisms and concrete degradation, this research suggests several machine-learning models as well as traditional multiple linear regression (MLR) model to predict the MIC in sewer pipelines. The models can be categorized into three sections: (i) stand-alone models (GMDH, GRNN, RBFNN, MLPNN, CHAID, and CART), (ii) integrative models (ANFIS and SVR with PSO, ABC and FA) and (iii) ensemble meta-learner Stepwise Regression model. After implementing the models, statistical measures, including RMSE, MAE, MBE, PCC, and Nash–Sutcliffe model efficiency (NSE) are considered for evaluating models' performances. The results indicate that the ensemble Meta-learner-SR model is significantly more precise than other models. They also demonstrate that using an integrative model can improve the accuracy of stand-alone models by at least up to 42 percent. The durability and lifespan of the sewer system is also estimated by the aid of the best predictive model (Meta-learner-SR) for two scenario cases of (i) gas phase and (ii) submerged conditions. It is concluded that the sewer systems have a considerably lower life span (24 years less) exposed to submerged sewage than the gas phase with 56 years of durability.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139528666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Case, H. Castaneda, Y. Ding, D. Narayanan, A. Khan, M. Cedeño, G. Peña
The influence of the microstructure on the resistance to pitting potential in austenitic stainless steel UNS N31603 is evaluated to explain the effect of the distribution of features such as carbides. Different microstructures were obtained by processing, via surface laser melting (SLM) and sensitized at 600°C, 700°C and 800°C. The test solution used for electrochemical testing included a buffer pH 8 brine at room conditions. The characterization of the passive conditions is done by using potentiodynamic, potentiostatic and Mott Schottky techniques. The results show that the UNS N31603 samples produced by SLM have higher passive layer stability. The correlation with the microstructural features attribute this to a lack of inclusions and carbides characteristic of the SLM process. The analysis of the experimental results using the point defect model description of the passive layer behavior indicates that the stability of the passive layer is a priori inversely proportional to both the metal cation and anion vacancy diffusivities. Experiments reveal the close dependence and explain the properties of the passive layer with respect to a Point defect model.
评估了奥氏体不锈钢 UNS N31603 的微观结构对抗点蚀电位的影响，以解释碳化物等特征分布的影响。通过表面激光熔化（SLM）和在 600°C、700°C 和 800°C 下敏化处理，获得了不同的微观结构。电化学测试所用的测试溶液包括室温条件下 pH 值为 8 的缓冲盐水。无源条件的表征是通过电位动力、电位静态和莫特-肖特基技术完成的。结果表明，通过 SLM 生产的 UNS N31603 样品具有更高的被动层稳定性。与微观结构特征的相关性表明，这是因为 SLM 工艺中缺少夹杂物和碳化物。使用点缺陷模型描述被动层行为对实验结果进行的分析表明，被动层的稳定性先验地与金属阳离子和阴离子空位扩散率成反比。实验揭示了点缺陷模型与被动层特性的密切关系并解释了被动层的特性。
{"title":"Characterization using point defect theory of the microstructure effect on passivity stability in austenitic stainless steel","authors":"R. Case, H. Castaneda, Y. Ding, D. Narayanan, A. Khan, M. Cedeño, G. Peña","doi":"10.5006/4365","DOIUrl":"https://doi.org/10.5006/4365","url":null,"abstract":"\u0000 The influence of the microstructure on the resistance to pitting potential in austenitic stainless steel UNS N31603 is evaluated to explain the effect of the distribution of features such as carbides. Different microstructures were obtained by processing, via surface laser melting (SLM) and sensitized at 600°C, 700°C and 800°C. The test solution used for electrochemical testing included a buffer pH 8 brine at room conditions.\u0000 The characterization of the passive conditions is done by using potentiodynamic, potentiostatic and Mott Schottky techniques. The results show that the UNS N31603 samples produced by SLM have higher passive layer stability. The correlation with the microstructural features attribute this to a lack of inclusions and carbides characteristic of the SLM process. The analysis of the experimental results using the point defect model description of the passive layer behavior indicates that the stability of the passive layer is a priori inversely proportional to both the metal cation and anion vacancy diffusivities. Experiments reveal the close dependence and explain the properties of the passive layer with respect to a Point defect model.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139620149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To reduce the consumption of zinc resources, it is necessary to reduce the zinc powder content of epoxy zinc-rich coatings. However, the reduced zinc powder content tends to reduce the degree of connectivity in the layer, which leads to a reduction in the corrosion resistance of the coating. The effective zinc powder content was also reduced. Therefore, it is important to increase the connection capacity of the zinc powder in the coating while reducing the amount of zinc powder. In this paper, an epoxy coating with low zinc content is prepared by using flake zinc powder instead of spherical zinc powder. It also uses graphene to connect zinc powder in the coating to increase the electrical conductivity of the zinc powder in the coating. This results in an increase in the protection of the coating determined, although the cathodic protection of the coating was not prolonged by the results of OCP and EIS. In addition, when the zinc powder in the coating is cleanly consumed, the complex nature of corrosion product formed with graphene can increase the barrier resistance of the coating thereby increasing the corrosion resistance.
为了减少锌资源的消耗，有必要降低环氧富锌涂层的锌粉含量。然而，锌粉含量的减少往往会降低涂层的连通度，从而导致涂层的耐腐蚀性降低。有效锌粉含量也随之降低。因此，在减少锌粉用量的同时，提高涂层中锌粉的连接能力非常重要。本文采用片状锌粉代替球状锌粉，制备了一种锌含量较低的环氧涂层。它还使用石墨烯连接涂层中的锌粉，以增加涂层中锌粉的导电性。虽然从 OCP 和 EIS 的结果来看，涂层的阴极保护时间并没有延长，但这还是提高了涂层的保护能力。此外，当涂层中的锌粉被消耗干净后，与石墨烯形成的腐蚀产物的复杂性质可以增加涂层的阻挡性，从而提高耐腐蚀性。
{"title":"Effect of graphene on corrosion resistance of low zinc epoxy coatings applied to low-carbon steel","authors":"","doi":"10.5006/4435","DOIUrl":"https://doi.org/10.5006/4435","url":null,"abstract":"\u0000 To reduce the consumption of zinc resources, it is necessary to reduce the zinc powder content of epoxy zinc-rich coatings. However, the reduced zinc powder content tends to reduce the degree of connectivity in the layer, which leads to a reduction in the corrosion resistance of the coating. The effective zinc powder content was also reduced. Therefore, it is important to increase the connection capacity of the zinc powder in the coating while reducing the amount of zinc powder. In this paper, an epoxy coating with low zinc content is prepared by using flake zinc powder instead of spherical zinc powder. It also uses graphene to connect zinc powder in the coating to increase the electrical conductivity of the zinc powder in the coating. This results in an increase in the protection of the coating determined, although the cathodic protection of the coating was not prolonged by the results of OCP and EIS. In addition, when the zinc powder in the coating is cleanly consumed, the complex nature of corrosion product formed with graphene can increase the barrier resistance of the coating thereby increasing the corrosion resistance.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139442422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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