Md Sojib Hossain, J. Skelton, William Moffat, James Fitz-Gerald
AA5083 is a solution-strengthened, supersaturated Al-Mg alloy. It has become widely used in corrosive and harsh environments, such as marine settings, due to its exceptional corrosion resistance and impressive strength-to-weight ratio. However, when exposed to moderately elevated temperatures, the alloy undergoes a process called sensitization, resulting in the precipitation of the β-phase. This intermetallic precipitate is rich in magnesium and has anodic properties, creating a micro-galvanic couple with the more noble aluminum (Al) matrix. Consequently, the sensitized alloy experiences intergranular corrosion due to the anodic dissolution of the grain boundary in a corrosive environment. Various techniques for dissolving intermetallic particles (IMPs) into the matrix have been reported in the literature, but they are often impractical for service components, and traditional solutionizing treatments tend to decrease mechanical properties. This study aimed to investigate the impact of pulsed excimer laser irradiation, as a novel approach, on the surface morphology, chemical composition, and electrochemical behavior of highly sensitized AA5083 samples. To achieve this, various analytical techniques were employed, including profilometry, optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and localized potentiostat scans. The results of this investigation showed that laser surface melting (LSM) led to a reduction in the open circuit potential (OCP) and cathodic current density in a 0.6 M NaCl aqueous solution, mainly due to increased surface homogenization. Furthermore, multiple grazing incident X-ray diffraction (GIXRD) scans were performed to identify the changes in the metallurgical and crystallographic parameters in the near-surface region. Anodic polarization scans of the LSM surface galvanically coupled with a more cathodic base metal exhibited a lower corrosion current density than the theoretical value suggested by mixed potential theory. The improved performance could potentially be attributed to the surface homogenization and formation of a robust passive layer on the LSM surface.
AA5083 是一种固溶强化的过饱和铝镁合金。由于其优异的耐腐蚀性和惊人的强度重量比，它已被广泛应用于腐蚀性和恶劣的环境中，如海洋环境。然而，当暴露在适度升高的温度下时，合金会经历一个称为敏化的过程，从而析出β相。这种金属间析出物富含镁，具有阳极特性，可与惰性较高的铝（Al）基体形成微电偶。因此，由于晶界在腐蚀环境中发生阳极溶解，敏化合金会出现晶间腐蚀。文献中报道了各种将金属间微粒（IMPs）溶解到基体中的技术，但这些技术对于使用中的部件来说往往不切实际，而且传统的固溶处理往往会降低机械性能。本研究旨在研究脉冲准分子激光辐照这种新方法对高度敏化 AA5083 样品的表面形态、化学成分和电化学行为的影响。为此，我们采用了多种分析技术，包括轮廓仪、光学显微镜、扫描电子显微镜 (SEM)、能量色散光谱仪 (EDS) 和局部恒电位仪扫描。研究结果表明，激光表面熔化（LSM）降低了 0.6 M NaCl 水溶液中的开路电位（OCP）和阴极电流密度，这主要是由于表面均匀化程度提高所致。此外，还进行了多次掠入射 X 射线衍射 (GIXRD) 扫描，以确定近表面区域冶金和晶体学参数的变化。对与阴极性更强的基体金属电耦合的 LSM 表面进行阳极极化扫描后发现，其腐蚀电流密度低于混合电位理论的理论值。性能的提高可能是由于表面均匀化以及在 LSM 表面形成了坚固的被动层。
{"title":"Laser Surface Melting to Mitigate Intergranular Corrosion of Sensitized AA 5083","authors":"Md Sojib Hossain, J. Skelton, William Moffat, James Fitz-Gerald","doi":"10.5006/4438","DOIUrl":"https://doi.org/10.5006/4438","url":null,"abstract":"AA5083 is a solution-strengthened, supersaturated Al-Mg alloy. It has become widely used in corrosive and harsh environments, such as marine settings, due to its exceptional corrosion resistance and impressive strength-to-weight ratio. However, when exposed to moderately elevated temperatures, the alloy undergoes a process called sensitization, resulting in the precipitation of the β-phase. This intermetallic precipitate is rich in magnesium and has anodic properties, creating a micro-galvanic couple with the more noble aluminum (Al) matrix. Consequently, the sensitized alloy experiences intergranular corrosion due to the anodic dissolution of the grain boundary in a corrosive environment. Various techniques for dissolving intermetallic particles (IMPs) into the matrix have been reported in the literature, but they are often impractical for service components, and traditional solutionizing treatments tend to decrease mechanical properties. This study aimed to investigate the impact of pulsed excimer laser irradiation, as a novel approach, on the surface morphology, chemical composition, and electrochemical behavior of highly sensitized AA5083 samples. To achieve this, various analytical techniques were employed, including profilometry, optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and localized potentiostat scans. The results of this investigation showed that laser surface melting (LSM) led to a reduction in the open circuit potential (OCP) and cathodic current density in a 0.6 M NaCl aqueous solution, mainly due to increased surface homogenization. Furthermore, multiple grazing incident X-ray diffraction (GIXRD) scans were performed to identify the changes in the metallurgical and crystallographic parameters in the near-surface region. Anodic polarization scans of the LSM surface galvanically coupled with a more cathodic base metal exhibited a lower corrosion current density than the theoretical value suggested by mixed potential theory. The improved performance could potentially be attributed to the surface homogenization and formation of a robust passive layer on the LSM surface.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139207461","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}
Yangmei Chen, Xiaoyan He, Hailong Zhang, Gang Chen, Xiuqin Bai
The work aims to provide a basis knowledge of corrosion behavior and corrosion kinetics of ocean engineering steel DH36 induced by Citrobacter farmeri. This study analyzed the corrosion product composition, corrosion morphology, electrochemical information, weight loss of DH36 in various corrosion systems. The results indicated that with the extension of soaking time, the corrosion products soaked in Citrobacter farmeri suspension were denser than those soaked in artificial seawater. At the initial immersion stage led to a higher uniform corrosion rate of DH36 in Citrobacter farmeri suspension compared to that in artificial seawater, which subsequently decreased over time. DH36 experienced primarily uniform corrosion when immersed in artificial seawater. In contrast, DH36 samples in Citrobacter farmeri suspension exhibited significant crevice corrosion, resulting in a maximum pit depth of 5.720 μm. Furthermore, the weight loss of DH36 in artificial seawater and Citrobacter farmeri suspension could be described by the power function formula D=0.0006t0.9579 and D=0.0007t0.7247, respectively. This study elucidates the fundamental mechanisms through which the presence of Citrobacter farmeri induces general and pitting corrosion of DH36 in a marine environment.
{"title":"Corrosion behavior of DH36 steel in the presence of acid-producing bacterium Citrobacter farmeri","authors":"Yangmei Chen, Xiaoyan He, Hailong Zhang, Gang Chen, Xiuqin Bai","doi":"10.5006/4430","DOIUrl":"https://doi.org/10.5006/4430","url":null,"abstract":"The work aims to provide a basis knowledge of corrosion behavior and corrosion kinetics of ocean engineering steel DH36 induced by Citrobacter farmeri. This study analyzed the corrosion product composition, corrosion morphology, electrochemical information, weight loss of DH36 in various corrosion systems. The results indicated that with the extension of soaking time, the corrosion products soaked in Citrobacter farmeri suspension were denser than those soaked in artificial seawater. At the initial immersion stage led to a higher uniform corrosion rate of DH36 in Citrobacter farmeri suspension compared to that in artificial seawater, which subsequently decreased over time. DH36 experienced primarily uniform corrosion when immersed in artificial seawater. In contrast, DH36 samples in Citrobacter farmeri suspension exhibited significant crevice corrosion, resulting in a maximum pit depth of 5.720 μm. Furthermore, the weight loss of DH36 in artificial seawater and Citrobacter farmeri suspension could be described by the power function formula D=0.0006t0.9579 and D=0.0007t0.7247, respectively. This study elucidates the fundamental mechanisms through which the presence of Citrobacter farmeri induces general and pitting corrosion of DH36 in a marine environment.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139204770","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}
Grouted, post-tensioned (PTd) concrete systems are widely used to construct bridges, typically with an anticipated corrosion-free service life of 100+ years. However, the usage of inadequate grout materials and grouting practices in PTd concrete systems have caused unwanted air voids in ducts, leading to strand-grout-air (SGA) interface, carbonation of exposed grout layer and localized corrosion of strands (say, within about 10 to 20 years). Re-grouting of voids as a tendon repair strategy has led to accelerated galvanic corrosion of the portion of strands at the interface between the carbonated base grout and repair grout with different chemistry, raising concerns and reluctance in re-grouting of voids in tendons. This work focused on understanding and quantifying the galvanic corrosion at the interface of carbonated base grout and repair grout in a re-grouted tendon. The theoretical analysis based on mixed potential theory estimated a galvanic current density of ≈ 2 μA/cm2 and showed that the galvanic coupling can increase the corrosion current density of the prestressing steel in the base grout by about two-fold. The study on prestressed steel in simulated solutions estimated a galvanic current density of ≈ 20 μA/cm2. Then, the study on prestressing steel in grouts and the analytical simulation estimated galvanic current densities around 1.5 to 2 μA/cm2 at 95% external relative humidity and 25 °C. A model relating the galvanic current density in grouted systems as a function of external relative humidity was developed, which showed an exponential increase in the galvanic corrosion with an increase in external relative humidity. Also, a case study showed that if the tendon anchorage region experiences 95% external relative humidity for about 20 years, sufficient strand corrosion could happen, and structural behavior can change from ductile to brittle nature, which could be a serious concern for structures in the coastal zone.
{"title":"Galvanic corrosion of strands in re-grouted, post-tensioned concrete bridges","authors":"Karthikeyan Manickam, R. Pillai","doi":"10.5006/4461","DOIUrl":"https://doi.org/10.5006/4461","url":null,"abstract":"Grouted, post-tensioned (PTd) concrete systems are widely used to construct bridges, typically with an anticipated corrosion-free service life of 100+ years. However, the usage of inadequate grout materials and grouting practices in PTd concrete systems have caused unwanted air voids in ducts, leading to strand-grout-air (SGA) interface, carbonation of exposed grout layer and localized corrosion of strands (say, within about 10 to 20 years). Re-grouting of voids as a tendon repair strategy has led to accelerated galvanic corrosion of the portion of strands at the interface between the carbonated base grout and repair grout with different chemistry, raising concerns and reluctance in re-grouting of voids in tendons. This work focused on understanding and quantifying the galvanic corrosion at the interface of carbonated base grout and repair grout in a re-grouted tendon. The theoretical analysis based on mixed potential theory estimated a galvanic current density of ≈ 2 μA/cm2 and showed that the galvanic coupling can increase the corrosion current density of the prestressing steel in the base grout by about two-fold. The study on prestressed steel in simulated solutions estimated a galvanic current density of ≈ 20 μA/cm2. Then, the study on prestressing steel in grouts and the analytical simulation estimated galvanic current densities around 1.5 to 2 μA/cm2 at 95% external relative humidity and 25 °C. A model relating the galvanic current density in grouted systems as a function of external relative humidity was developed, which showed an exponential increase in the galvanic corrosion with an increase in external relative humidity. Also, a case study showed that if the tendon anchorage region experiences 95% external relative humidity for about 20 years, sufficient strand corrosion could happen, and structural behavior can change from ductile to brittle nature, which could be a serious concern for structures in the coastal zone.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139205448","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}
Sérgio Leonardo Butski Soares Santos, B. P. da Silva, Fernanda Gabriel de Freitas, Idalina Vieira Aoki, Vera Rosa Capelossi
One way to protect carbon steel from corrosion is through pre-treatment and corrosion inhibitors, such as the use of silane layers that can protect against corrosion. In this study, the corrosion resistance of the TEOS/GPTMS (Tetraethyl orthosilicate / 3-Glycidoxypropyltrimethoxysilane) hybrid film modified with garlic peel powder or cocoa shell powder on carbon steel was evaluated. By electrochemical impedance spectroscopy (EIS) it was observed that the incorporation of inhibitors promoted higher values of impedance modulus compared to the bare metal substrate or in absence of inhibitor, and the concentration of 1.77 g L−1 provided the best performance for both natural inhibitors. The Fourier transform infrared spectroscopy (FTIR) showed that the addition of inhibitors to the hybrid film promoted a better hydrolysis in the formation of the films. By the Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM/EDS) it was noted that there was the formation of the hybrid film on the metal surface, and the insertion of the inhibitor to the silane film enabled the formation of grains that precipitate from the deposition of the inhibitor on the substrate surface. The Scanning Vibrating Electrode Technique (SVET) shows that the inhibitors improved corrosion resistance of the hybrid film, corroborating with the EIS analysis. The contact angle shows that the presence of the inhibitor in the silane film makes it less hydrophilic. The roughness profile shows that the hybrid film with cocoa has the highest roughness represented by a higher average value of Average Roughness (Rz).
保护碳钢免受腐蚀的方法之一是通过预处理和腐蚀抑制剂，例如使用硅烷层来防止腐蚀。本研究评估了用大蒜皮粉或可可壳粉修饰的 TEOS/GPTMS（正硅酸四乙酯/3-缩水甘油氧丙基三甲氧基硅烷）混合膜在碳钢上的耐腐蚀性。通过电化学阻抗光谱（EIS）观察到，与裸金属基底或没有抑制剂的情况相比，抑制剂的加入会使阻抗模量值升高，而 1.77 g L-1 的浓度为两种天然抑制剂提供了最佳性能。傅立叶变换红外光谱（FTIR）显示，在混合薄膜中添加抑制剂能更好地促进薄膜的水解。扫描电子显微镜和能量色散光谱仪（SEM/EDS）显示，金属表面形成了混合膜，在硅烷膜中加入抑制剂后，抑制剂在基底表面沉积形成了晶粒。扫描振动电极技术（SVET）表明，抑制剂提高了混合薄膜的耐腐蚀性，这与 EIS 分析结果相吻合。接触角显示，硅烷薄膜中抑制剂的存在使其亲水性降低。粗糙度曲线显示，含有可可的混合薄膜的粗糙度最高，平均粗糙度 (Rz) 的平均值较高。
{"title":"Pre-treatment of Carbon Steel with Hybrid Film Modified with Different Natural Inhibitors (Garlic and Cocoa)","authors":"Sérgio Leonardo Butski Soares Santos, B. P. da Silva, Fernanda Gabriel de Freitas, Idalina Vieira Aoki, Vera Rosa Capelossi","doi":"10.5006/4324","DOIUrl":"https://doi.org/10.5006/4324","url":null,"abstract":"One way to protect carbon steel from corrosion is through pre-treatment and corrosion inhibitors, such as the use of silane layers that can protect against corrosion. In this study, the corrosion resistance of the TEOS/GPTMS (Tetraethyl orthosilicate / 3-Glycidoxypropyltrimethoxysilane) hybrid film modified with garlic peel powder or cocoa shell powder on carbon steel was evaluated. By electrochemical impedance spectroscopy (EIS) it was observed that the incorporation of inhibitors promoted higher values of impedance modulus compared to the bare metal substrate or in absence of inhibitor, and the concentration of 1.77 g L−1 provided the best performance for both natural inhibitors. The Fourier transform infrared spectroscopy (FTIR) showed that the addition of inhibitors to the hybrid film promoted a better hydrolysis in the formation of the films. By the Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM/EDS) it was noted that there was the formation of the hybrid film on the metal surface, and the insertion of the inhibitor to the silane film enabled the formation of grains that precipitate from the deposition of the inhibitor on the substrate surface. The Scanning Vibrating Electrode Technique (SVET) shows that the inhibitors improved corrosion resistance of the hybrid film, corroborating with the EIS analysis. The contact angle shows that the presence of the inhibitor in the silane film makes it less hydrophilic. The roughness profile shows that the hybrid film with cocoa has the highest roughness represented by a higher average value of Average Roughness (Rz).","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257539","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}
Neda Norooziasl, David Young, Bruce Brown, Marc Singer
The effect of a paraffinic model oil (LVT-200) containing select surface-active compounds (myristic acid and acridine) on CO2 corrosion with and without intermittent wetting has been studied. Observations have shown that the presence of myristic acid in the oil phase has no effect on corrosion behavior due to its lack of partitioning in the water phase. However, after direct contact between the oil phase containing myristic acid and the metal surface, there was a significant decrease in the corrosion rate. This phenomenon gradually diminished at pH 4.0 but was more persistent at pH 6.5. The presence of acridine in the oil phase was shown to have a strong inhibitive effect at pH 4.0, even during the partitioning step. The partitioning of acridine from the oil phase to the water phase at pH 4.0 was confirmed by Ultraviolet-Visible spectroscopy (UV-Vis) results. However, there was no inhibitive effect conferred by the presence of acridine on the corrosion rate at pH 6.5. An experimental methodology was developed that facilitated improved simulation of the effect of intermittent oil/water wetting on CO2 corrosion. The electrochemical current response during the oil/water intermittent wetting cycles showed that persistency of model oil (without surface active compounds) on the mild steel surface is only a matter of seconds. Corrosion rate measurements showed that the presence of myristic acid renders the oil layer more persistent after intermittent wetting as compared to one-time direct contact.
{"title":"Effect of Oil/Water Intermittent Wetting on CO2 Corrosion in the Presence of Acridine and Myristic Acid","authors":"Neda Norooziasl, David Young, Bruce Brown, Marc Singer","doi":"10.5006/4434","DOIUrl":"https://doi.org/10.5006/4434","url":null,"abstract":"The effect of a paraffinic model oil (LVT-200) containing select surface-active compounds (myristic acid and acridine) on CO2 corrosion with and without intermittent wetting has been studied. Observations have shown that the presence of myristic acid in the oil phase has no effect on corrosion behavior due to its lack of partitioning in the water phase. However, after direct contact between the oil phase containing myristic acid and the metal surface, there was a significant decrease in the corrosion rate. This phenomenon gradually diminished at pH 4.0 but was more persistent at pH 6.5. The presence of acridine in the oil phase was shown to have a strong inhibitive effect at pH 4.0, even during the partitioning step. The partitioning of acridine from the oil phase to the water phase at pH 4.0 was confirmed by Ultraviolet-Visible spectroscopy (UV-Vis) results. However, there was no inhibitive effect conferred by the presence of acridine on the corrosion rate at pH 6.5. An experimental methodology was developed that facilitated improved simulation of the effect of intermittent oil/water wetting on CO2 corrosion. The electrochemical current response during the oil/water intermittent wetting cycles showed that persistency of model oil (without surface active compounds) on the mild steel surface is only a matter of seconds. Corrosion rate measurements showed that the presence of myristic acid renders the oil layer more persistent after intermittent wetting as compared to one-time direct contact.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257568","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}
{"title":"EDITORIAL: 2023 in Review","authors":"","doi":"10.5006/4487","DOIUrl":"https://doi.org/10.5006/4487","url":null,"abstract":"","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139269405","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}
J. S. J. Tizzile, J. Jyothymol, Arunchandran Chenan
The corrosion inhibition effectiveness of dissolved Li2CO3 and Li2C2O4 was studied for Mg alloy AZ31 B in 0.1 M NaCl solution. The electrochemical and corrosion inhibition properties of Li salts were studied using potentiodynamic polarization (PDP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and H2 evolution measurement methods. The corrosion inhibition efficiency as a function of immersion time was also investigated. The morphology and chemical composition of AZ31 B surfaces after 24 h immersion in 0.1 M NaCl with and without the addition of dissolved Li salts revealed considerable differences in corrosion properties. The role of Li+ ions, CO32- ions, and C2O42- on corrosion inhibition of AZ31 B was focused and their role in the corrosion inhibition was discussed. Li2CO3 had better corrosion inhibition efficiency compared to Li2C2O4 in 0.1 M NaCl solution at ambient temperature. The optimum concentration of Li2CO3 was 50 mM to provide the highest corrosion inhibition efficiency of 96.75 %, while the optimum concentration and inhibition efficiency for Li2C2O4 were 3 mM and 82.84 % respectively. Surface characterization of the Li2CO3 inhibited AZ31 B revealed that the enhanced corrosion protection was due to the formation of a protective layer mainly composed of MgCO3. Corrosion studies over time showed that Li2CO3 could effectively provide corrosion protection for 48 h, while Li2C2O4 became ineffective after 12 h of immersion in 0.1 M NaCl.
研究了溶解的 Li2CO3 和 Li2C2O4 在 0.1 M NaCl 溶液中对镁合金 AZ31 B 的缓蚀效果。采用电位极化（PDP）、线性极化电阻（LPR）、电化学阻抗谱（EIS）和 H2 演化测量方法研究了锂盐的电化学和缓蚀特性。此外，还研究了腐蚀抑制效率与浸泡时间的函数关系。在加入和未加入溶解锂盐的 0.1 M NaCl 溶液中浸泡 24 小时后，AZ31 B 表面的形态和化学成分显示其腐蚀性能存在很大差异。重点研究了 Li+ 离子、CO32- 离子和 C2O42- 对 AZ31 B 的缓蚀作用，并讨论了它们在缓蚀中的作用。在常温下的 0.1 M NaCl 溶液中，与 Li2C2O4 相比，Li2CO3 的缓蚀效率更高。Li2CO3 的最佳浓度为 50 mM，缓蚀效率最高，达到 96.75%，而 Li2C2O4 的最佳浓度和缓蚀效率分别为 3 mM 和 82.84%。Li2CO3 抑制的 AZ31 B 的表面表征显示，腐蚀保护的增强是由于形成了主要由 MgCO3 组成的保护层。随时间变化的腐蚀研究表明，Li2CO3 可以在 48 小时内有效地提供腐蚀保护，而 Li2C2O4 在 0.1 M NaCl 中浸泡 12 小时后就失效了。
{"title":"Lithium Carbonate and Oxalate Salts as Corrosion Inhibitors for Magnesium Alloy AZ31 B in NaCl Solution","authors":"J. S. J. Tizzile, J. Jyothymol, Arunchandran Chenan","doi":"10.5006/4418","DOIUrl":"https://doi.org/10.5006/4418","url":null,"abstract":"The corrosion inhibition effectiveness of dissolved Li2CO3 and Li2C2O4 was studied for Mg alloy AZ31 B in 0.1 M NaCl solution. The electrochemical and corrosion inhibition properties of Li salts were studied using potentiodynamic polarization (PDP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and H2 evolution measurement methods. The corrosion inhibition efficiency as a function of immersion time was also investigated. The morphology and chemical composition of AZ31 B surfaces after 24 h immersion in 0.1 M NaCl with and without the addition of dissolved Li salts revealed considerable differences in corrosion properties. The role of Li+ ions, CO32- ions, and C2O42- on corrosion inhibition of AZ31 B was focused and their role in the corrosion inhibition was discussed. Li2CO3 had better corrosion inhibition efficiency compared to Li2C2O4 in 0.1 M NaCl solution at ambient temperature. The optimum concentration of Li2CO3 was 50 mM to provide the highest corrosion inhibition efficiency of 96.75 %, while the optimum concentration and inhibition efficiency for Li2C2O4 were 3 mM and 82.84 % respectively. Surface characterization of the Li2CO3 inhibited AZ31 B revealed that the enhanced corrosion protection was due to the formation of a protective layer mainly composed of MgCO3. Corrosion studies over time showed that Li2CO3 could effectively provide corrosion protection for 48 h, while Li2C2O4 became ineffective after 12 h of immersion in 0.1 M NaCl.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139269651","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}
The oxidation and stress corrosion cracking (SCC) behaviors of Alloy 52M buttering (52Mb) layer were studied in simulated pressurized water reactor (PWR) primary water after microstructure characterization. The 52Mb layer was first post-weld heat treatment (1st-PWHT) and follow-up PWHT (FU-PWHT). Two dilution zones (DZs) were found in both the 1st-PWHT and FU-PWHT 52Mb samples. FU-PWHT decreased the Cr content in the first dilution zone, enhancing the oxidation rate and accelerating the formation of the local oxidation penetration zone at the oxide/substrate interface. Lower Cr content and high Fe content in the dilution zone were detrimental to the SCC resistance of the 52Mb in PWR primary water.
{"title":"Effects of matrix and dendrite boundary composition on stress corrosion cracking performance of Alloy 52M buttering layer in simulated PWR primary water","authors":"Jiarong Ma, Qi Xiong, Xinhe Xu, Tongmin Cui, Zhanpeng Lu, Tetsuo Shoji","doi":"10.5006/4392","DOIUrl":"https://doi.org/10.5006/4392","url":null,"abstract":"The oxidation and stress corrosion cracking (SCC) behaviors of Alloy 52M buttering (52Mb) layer were studied in simulated pressurized water reactor (PWR) primary water after microstructure characterization. The 52Mb layer was first post-weld heat treatment (1st-PWHT) and follow-up PWHT (FU-PWHT). Two dilution zones (DZs) were found in both the 1st-PWHT and FU-PWHT 52Mb samples. FU-PWHT decreased the Cr content in the first dilution zone, enhancing the oxidation rate and accelerating the formation of the local oxidation penetration zone at the oxide/substrate interface. Lower Cr content and high Fe content in the dilution zone were detrimental to the SCC resistance of the 52Mb in PWR primary water.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139268877","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}
Dannisa R. Chalfoun, Mariano A. Kappes, Teresa E. Perez, José L. Otegui, Mariano Iannuzzi
ABSTRACT In the first part of this paper, trenches were reported for Ni-containing steels tested using the slow strain rate test method in H2S-containing environments at the open circuit potential. Trenches are deep elongated pits, and their appearance is more alike to small blunt cracks. These features can develop a sharp sulfide stress crack at their bottom under certain conditions, which are still not fully understood. In this second and final part, the effect of the electrochemical potential and the stress level in trench nucleation and growth was investigated for the same set of Ni-containing steels with up to 5 wt.% Ni. The anodic nature of the trench formation mechanism was verified, and under an anodic polarization a critical stress value for trench formation, σtrench, was estimated from slow strain rate tests and finite element modeling. Applying a cathodic potential suppressed trench formation, but not cracking, because cracks nucleated and propagated by hydrogen stress cracking (HSC). The resulting environmental and stress-level dependencies for Ni steels confirmed that trenches could be considered a form of environmental-assisted cracking. It is concluded that the main role of trenches is to provide favorable spots for hydrogen stress crack nucleation at OCP, but their presence is neither necessary nor sufficient for cracking occurrence.
{"title":"The Role of Nickel in Low Alloy Steels exposed to H2S-containing environments. Part II: Effect of the Electrochemical Potential and Stress Level on Trench Formation","authors":"Dannisa R. Chalfoun, Mariano A. Kappes, Teresa E. Perez, José L. Otegui, Mariano Iannuzzi","doi":"10.5006/4437","DOIUrl":"https://doi.org/10.5006/4437","url":null,"abstract":"ABSTRACT In the first part of this paper, trenches were reported for Ni-containing steels tested using the slow strain rate test method in H2S-containing environments at the open circuit potential. Trenches are deep elongated pits, and their appearance is more alike to small blunt cracks. These features can develop a sharp sulfide stress crack at their bottom under certain conditions, which are still not fully understood. In this second and final part, the effect of the electrochemical potential and the stress level in trench nucleation and growth was investigated for the same set of Ni-containing steels with up to 5 wt.% Ni. The anodic nature of the trench formation mechanism was verified, and under an anodic polarization a critical stress value for trench formation, σtrench, was estimated from slow strain rate tests and finite element modeling. Applying a cathodic potential suppressed trench formation, but not cracking, because cracks nucleated and propagated by hydrogen stress cracking (HSC). The resulting environmental and stress-level dependencies for Ni steels confirmed that trenches could be considered a form of environmental-assisted cracking. It is concluded that the main role of trenches is to provide favorable spots for hydrogen stress crack nucleation at OCP, but their presence is neither necessary nor sufficient for cracking occurrence.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135476032","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}
Ali Riahi, Hao Zhu, Ali Eskandari, Suraj Y. Persaud, Roger C. Newman
ABSTRACT The oxidation behavior of Alloy 690 and Ni-xCr-10Fe model alloys exposed to 480 °C hydrogenated steam, in the nickel metal stability region, was studied using a variety of techniques, including time-resolved Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Electron Energy Loss Spectroscopy (EELS). The alloy underwent internal oxidation intragranularly, resulting in the expulsion of metallic Ni nodules to the surface. A compact Cr-rich “healing” layer developed over time at the intragranular internal oxidation front near grain boundaries and significantly retards further internal oxidation. Protective external Cr-rich oxide formed at and very near the grain boundaries, hindering intergranular oxidation. In view of the fact that the protective oxide forms micrometres away from the grain boundaries, one cannot simply say that Cr diffuses up the boundary and forms an oxide which spreads laterally – internal stress relief must play a role, just as it does within the grains, only with different mechanisms at play.
{"title":"New insights into internal oxidation of alloy 690 and model alloys in hydrogenated steam","authors":"Ali Riahi, Hao Zhu, Ali Eskandari, Suraj Y. Persaud, Roger C. Newman","doi":"10.5006/4439","DOIUrl":"https://doi.org/10.5006/4439","url":null,"abstract":"ABSTRACT The oxidation behavior of Alloy 690 and Ni-xCr-10Fe model alloys exposed to 480 °C hydrogenated steam, in the nickel metal stability region, was studied using a variety of techniques, including time-resolved Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Electron Energy Loss Spectroscopy (EELS). The alloy underwent internal oxidation intragranularly, resulting in the expulsion of metallic Ni nodules to the surface. A compact Cr-rich “healing” layer developed over time at the intragranular internal oxidation front near grain boundaries and significantly retards further internal oxidation. Protective external Cr-rich oxide formed at and very near the grain boundaries, hindering intergranular oxidation. In view of the fact that the protective oxide forms micrometres away from the grain boundaries, one cannot simply say that Cr diffuses up the boundary and forms an oxide which spreads laterally – internal stress relief must play a role, just as it does within the grains, only with different mechanisms at play.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136022945","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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