There has been concern that prestressing structural steel contained within galvanized bridge tendon ducts may become embrittled due to excessive galvanic coupling with the duct of which may be exacerbated by deficiencies within the grout fill. The objective of this work is to quantify the level of galvanic coupling achievable as a function of grout condition and to assess whether such conditions may promote water reduction and hydrogen absorption. Experimental tendon assemblies were used to quantify galvanic coupling considering a single prestressing steel wire and various grout conditions. The results were related to more realistic geometric configurations by simulations considering a range of possible kinetic boundary conditions. A model is used to estimate the amount of hydrogen that may be absorbed as a function of time considering the coupling current density.
{"title":"Implications of grout condition on galvanic coupling and hydrogen absorption within post-tensioned bridge tendons constructed with galvanized steel ducts","authors":"David Dukeman, Christopher L. Alexander","doi":"10.5006/4590","DOIUrl":"https://doi.org/10.5006/4590","url":null,"abstract":"\u0000 There has been concern that prestressing structural steel contained within galvanized bridge tendon ducts may become embrittled due to excessive galvanic coupling with the duct of which may be exacerbated by deficiencies within the grout fill. The objective of this work is to quantify the level of galvanic coupling achievable as a function of grout condition and to assess whether such conditions may promote water reduction and hydrogen absorption. Experimental tendon assemblies were used to quantify galvanic coupling considering a single prestressing steel wire and various grout conditions. The results were related to more realistic geometric configurations by simulations considering a range of possible kinetic boundary conditions. A model is used to estimate the amount of hydrogen that may be absorbed as a function of time considering the coupling current density.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141805371","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}
Data for mass loss of a variety of magnesium alloys as a function of exposure period show that corrosion loss follows bimodal trending with time for different exposure environments, both laboratory and field support these findings. For data sets sufficient to discriminate bimodal behaviour, the instantaneous rate of corrosion at the commencement of the second mode is (close to) 4 times the instantaneous rate of corrosion at the end of the first mode (i.e. through the transition period). This observation is consistent with the theoretical relative diffusivities of oxygen and hydrogen through the corrosion product layer as it exists during the transition period. These findings support the notion that the bimodal model has corrosion in Mode 1 rate-controlled by the cathodic oxygen reduction reaction and the inward diffusion of oxygen while in Mode 2 corrosion is rate-controlled by the cathodic hydrogen evolution reaction and the outward diffusion of hydrogen. Similar findings have been made previously for various ferrous and other alloys and thus throws new light on the development of corrosion of magnesium alloys. It also provides reasons for measurements of hydrogen evolution and for electrochemical techniques underestimating magnesium corrosion rates. A new procedure for combining these is proposed.
{"title":"Bimodal trending in corrosion loss of magnesium alloys","authors":"R. Melchers","doi":"10.5006/4548","DOIUrl":"https://doi.org/10.5006/4548","url":null,"abstract":"\u0000 Data for mass loss of a variety of magnesium alloys as a function of exposure period show that corrosion loss follows bimodal trending with time for different exposure environments, both laboratory and field support these findings. For data sets sufficient to discriminate bimodal behaviour, the instantaneous rate of corrosion at the commencement of the second mode is (close to) 4 times the instantaneous rate of corrosion at the end of the first mode (i.e. through the transition period). This observation is consistent with the theoretical relative diffusivities of oxygen and hydrogen through the corrosion product layer as it exists during the transition period. These findings support the notion that the bimodal model has corrosion in Mode 1 rate-controlled by the cathodic oxygen reduction reaction and the inward diffusion of oxygen while in Mode 2 corrosion is rate-controlled by the cathodic hydrogen evolution reaction and the outward diffusion of hydrogen. Similar findings have been made previously for various ferrous and other alloys and thus throws new light on the development of corrosion of magnesium alloys. It also provides reasons for measurements of hydrogen evolution and for electrochemical techniques underestimating magnesium corrosion rates. A new procedure for combining these is proposed.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141814859","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}
Shifang Li, Zhu Xiao, Mei Fang, Haofeng Xie, Lijun Peng
A novel Cu-10Ni-1.7Fe-0.5Mn-0.2Cr alloy was fabricated and exposed to neutral 3.5 wt.% NaCl solution for various days. The corrosion performance, corrosion film, and corrosion mode of the alloy were investigated in detail. The results suggested that the average corrosion rate reduced from 0.082 mm/a for one-day immersion sample to 0.037 mm/a for thirty-day immersion sample. The reduction in corrosion rate was mainly attributed to the progressive thickness and densification of the corrosion film, leading to increasing the resistance of corrosion film with the prolonging exposure time. Low-valent oxides and chlorinated compounds were generated over the one-day immersion sample surface, while high-valent oxides and hydroxide compounds were developed over the thirty-day immersion sample surface. The mature corrosion film typically composed of Cu2O, CuO, Cu2(OH)3Cl, γ-FeOOH, MnO2, and Cr2O3. Eventually, the alloys suffered from the selective corrosion and intergranular corrosion after a long exposure time in NaCl solution.
{"title":"Corrosion behavior of Cu-Ni-Fe-Mn-Cr alloy in 3.5 wt.% NaCl solution","authors":"Shifang Li, Zhu Xiao, Mei Fang, Haofeng Xie, Lijun Peng","doi":"10.5006/4553","DOIUrl":"https://doi.org/10.5006/4553","url":null,"abstract":"\u0000 A novel Cu-10Ni-1.7Fe-0.5Mn-0.2Cr alloy was fabricated and exposed to neutral 3.5 wt.% NaCl solution for various days. The corrosion performance, corrosion film, and corrosion mode of the alloy were investigated in detail. The results suggested that the average corrosion rate reduced from 0.082 mm/a for one-day immersion sample to 0.037 mm/a for thirty-day immersion sample. The reduction in corrosion rate was mainly attributed to the progressive thickness and densification of the corrosion film, leading to increasing the resistance of corrosion film with the prolonging exposure time. Low-valent oxides and chlorinated compounds were generated over the one-day immersion sample surface, while high-valent oxides and hydroxide compounds were developed over the thirty-day immersion sample surface. The mature corrosion film typically composed of Cu2O, CuO, Cu2(OH)3Cl, γ-FeOOH, MnO2, and Cr2O3. Eventually, the alloys suffered from the selective corrosion and intergranular corrosion after a long exposure time in NaCl solution.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141829592","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}
Ahmad Raza Khan Rana, Shahzad Karim, Salwa AlAchkaar, Jamal Umer, Graham Brigham, G. Jarjoura
Thermally Sprayed Aluminum (TSA) protects against internal and external corrosion in many industrial applications. Even though TSA coating has been the subject of many studies, there is still a need to gain better insights into the degradation mechanisms of the TSA especially under immersion conditions and moisture-saturated thermal insulations. This study addresses the corrosion behavior of TSA in a CUI simulation setup (per ASTM G189-07) and autoclave immersion. The corrosion tests were conducted for three and four days under isothermal wet (IW) and cyclic wet (CW) conditions. Linear polarization resistance (LPR) scans were conducted during both (i.e., CUI simulation and autoclave immersion tests) to better understand the corrosion behaviors of TSA coating. Following corrosion testing, thorough microstructural examinations were conducted employing confocal laser microscopy, 3D topography, scanning electron microscopy (SEM), and Energy dispersive spectroscopy (EDS) to understand the microstructural and tribological changes resulting from corrosion testing. TSA coating under the insulation showed significant degradation via flashing moisture and active dissolution of iron at the insulation-metal interface. Unlike immersion conditions, the wear of TSA due to flashing moisture under thermal insulation created the crevices that caused the active corrosion of the steel substrate.
{"title":"An Investigation of Corrosion Behaviors of Thermally Sprayed Aluminum (TSA) at Elevated Temperatures Under Thermal Insulations and Autoclave Immersion Conditions","authors":"Ahmad Raza Khan Rana, Shahzad Karim, Salwa AlAchkaar, Jamal Umer, Graham Brigham, G. Jarjoura","doi":"10.5006/4508","DOIUrl":"https://doi.org/10.5006/4508","url":null,"abstract":"\u0000 Thermally Sprayed Aluminum (TSA) protects against internal and external corrosion in many industrial applications. Even though TSA coating has been the subject of many studies, there is still a need to gain better insights into the degradation mechanisms of the TSA especially under immersion conditions and moisture-saturated thermal insulations. This study addresses the corrosion behavior of TSA in a CUI simulation setup (per ASTM G189-07) and autoclave immersion. The corrosion tests were conducted for three and four days under isothermal wet (IW) and cyclic wet (CW) conditions. Linear polarization resistance (LPR) scans were conducted during both (i.e., CUI simulation and autoclave immersion tests) to better understand the corrosion behaviors of TSA coating. Following corrosion testing, thorough microstructural examinations were conducted employing confocal laser microscopy, 3D topography, scanning electron microscopy (SEM), and Energy dispersive spectroscopy (EDS) to understand the microstructural and tribological changes resulting from corrosion testing. TSA coating under the insulation showed significant degradation via flashing moisture and active dissolution of iron at the insulation-metal interface. Unlike immersion conditions, the wear of TSA due to flashing moisture under thermal insulation created the crevices that caused the active corrosion of the steel substrate.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141684711","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}
Kun Fang, Zhenliang Liu, Xinyao Zhang, Xiaoqin Zha
Cables have usually served as critical and vulnerable structural components in long span cable-supported bridges. Cable inspections revealed that corrosion, fatigue or coupled corrosion-fatigue were the ones of the main failure mechanisms. This paper proposed a stochastic modelling method for three-dimensional (3-D) corrosion pits of high-strength bridge wires, which can be applied to rapid fatigue life evaluation according to mass loss caused by surface corrosion pits of bridge wires nondestructively. High-strength steel wire specimens dismantled from the cable-stayed bridge served for 15 years were scanned to obtain the original surface corrosion data. The spatial position coordinate of corrosion pits were considered as random variable and can be well fitted by uniform distribution. While the number of corrosion pits can be fitted with generalized extreme value (GEV) distribution. The uniform corrosion depth du, which can be equivalent to mass loss rate, was calculated as the input corrosion parameter for 3-D corrosion pit modelling. The maximum pitting depth dmax for the steel wire was found to be associated with du. The geometric parameters for individual corrosion pits were recognized as pit depth d, depth-to-width ratio d/b, and aspect ratio b/a, which were fitted with different probability distributions. What follows is 3-D spatial corrosion pits simulation based on the individual corrosion parameter that were sampled and combined from the corresponding probabilistic distributions. Hereafter, fatigue life evaluation of corroded wires was conducted based on equivalent surface defect method and compared with the experimental results, verifying the effectiveness of the proposed modelling approaches.
在大跨度缆索支撑桥梁中，缆索通常是关键和脆弱的结构部件。缆索检测表明，腐蚀、疲劳或腐蚀-疲劳耦合是主要的失效机理。本文提出了一种高强度桥梁拉索三维（3-D）腐蚀坑随机建模方法，可根据桥梁拉索表面腐蚀坑造成的质量损失进行非破坏性的快速疲劳寿命评估。从使用了 15 年的斜拉桥上拆卸下来的高强度钢丝试样通过扫描获得了原始的表面腐蚀数据。腐蚀坑的空间位置坐标被视为随机变量，可以很好地拟合为均匀分布。腐蚀坑的数量可以用广义极值（GEV）分布拟合。计算出的均匀腐蚀深度 du 相当于质量损失率，作为三维腐蚀坑建模的输入腐蚀参数。发现钢丝的最大点蚀深度 dmax 与 du 有关。单个腐蚀坑的几何参数被确认为坑深 d、深宽比 d/b 和长宽比 b/a，并用不同的概率分布进行拟合。接下来将根据从相应概率分布中采样和组合的单个腐蚀参数进行三维空间腐蚀坑模拟。随后，根据等效表面缺陷法对腐蚀导线进行了疲劳寿命评估，并与实验结果进行了比较，从而验证了所提出的建模方法的有效性。
{"title":"A stochastic modeling method for three-dimensional corrosion pits of bridge cable wires and its application","authors":"Kun Fang, Zhenliang Liu, Xinyao Zhang, Xiaoqin Zha","doi":"10.5006/4541","DOIUrl":"https://doi.org/10.5006/4541","url":null,"abstract":"\u0000 Cables have usually served as critical and vulnerable structural components in long span cable-supported bridges. Cable inspections revealed that corrosion, fatigue or coupled corrosion-fatigue were the ones of the main failure mechanisms. This paper proposed a stochastic modelling method for three-dimensional (3-D) corrosion pits of high-strength bridge wires, which can be applied to rapid fatigue life evaluation according to mass loss caused by surface corrosion pits of bridge wires nondestructively. High-strength steel wire specimens dismantled from the cable-stayed bridge served for 15 years were scanned to obtain the original surface corrosion data. The spatial position coordinate of corrosion pits were considered as random variable and can be well fitted by uniform distribution. While the number of corrosion pits can be fitted with generalized extreme value (GEV) distribution. The uniform corrosion depth du, which can be equivalent to mass loss rate, was calculated as the input corrosion parameter for 3-D corrosion pit modelling. The maximum pitting depth dmax for the steel wire was found to be associated with du. The geometric parameters for individual corrosion pits were recognized as pit depth d, depth-to-width ratio d/b, and aspect ratio b/a, which were fitted with different probability distributions. What follows is 3-D spatial corrosion pits simulation based on the individual corrosion parameter that were sampled and combined from the corresponding probabilistic distributions. Hereafter, fatigue life evaluation of corroded wires was conducted based on equivalent surface defect method and compared with the experimental results, verifying the effectiveness of the proposed modelling approaches.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141351003","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}
Ming Liu, Guanghu Yao, Xuehan Wang, Lining Xu, Lang Jiao, Hang Su, Anqing Fu
This study investigated the coupling effect of hydrogen and precipitates on the initiation of pitting using HR3C stainless steel with large NbCrN precipitates as the study material. Stainless steel exhibited good resistance to pitting when not subject to hydrogen charging. Hydrogen charging significantly reduced the corrosion resistance and stability of the passive film. Results obtained using the hydrogen microprint technique revealed that hydrogen was enriched within NbCrN precipitates and along the precipitate–substrate interface. Through immersion experiments, we discovered that pits preferentially initiated at the precipitate–substrate interface because it had weaker corrosion resistance than the precipitates.
{"title":"Coupling Effect of Precipitates and Hydrogen on Pitting Corrosion of Stainless Steel","authors":"Ming Liu, Guanghu Yao, Xuehan Wang, Lining Xu, Lang Jiao, Hang Su, Anqing Fu","doi":"10.5006/4549","DOIUrl":"https://doi.org/10.5006/4549","url":null,"abstract":"\u0000 This study investigated the coupling effect of hydrogen and precipitates on the initiation of pitting using HR3C stainless steel with large NbCrN precipitates as the study material. Stainless steel exhibited good resistance to pitting when not subject to hydrogen charging. Hydrogen charging significantly reduced the corrosion resistance and stability of the passive film. Results obtained using the hydrogen microprint technique revealed that hydrogen was enriched within NbCrN precipitates and along the precipitate–substrate interface. Through immersion experiments, we discovered that pits preferentially initiated at the precipitate–substrate interface because it had weaker corrosion resistance than the precipitates.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141351482","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}
Reinforced concrete and steel structural elements undergo premature degradation and lose strength primarily due to corrosion. Corrosion is an electrochemical phenomenon and its severity depends on number of environmental factors. Experimental data on corrosion of steel is important for making engineering decisions towards improving the service life of civil infrastructures. No recent dataset on atmospheric steel corrosion under Indian coastal environment is found to be available in the literature, and hence this research attempts to address some of the literature gap. This paper presents experimental study conducted to determine the corrosion rate of TMT, high-chromium steel (CRS) and stainless steel rebars exposed in actual coastal and inland regions for a period of one year. The site locations were located in southeastern parts of Tamilnadu state in India. Based on the first-year corrosion rate, the corrosion rate after extended exposure (10-years) was determined based on ISO 9224 recommendations. Atmospheric steel corrosion map of Tamilnadu state was developed using inverse distance interpolation technique. Microstructural studies indicated the formation of lepidocrocite (γ-FeOOH) phase composition in the rust products collected from coastal region.
钢筋混凝土和钢结构构件会过早退化并失去强度，这主要是由于腐蚀造成的。腐蚀是一种电化学现象，其严重程度取决于多种环境因素。有关钢材腐蚀的实验数据对于提高民用基础设施使用寿命的工程决策非常重要。文献中没有关于印度沿海环境下大气钢腐蚀的最新数据集，因此本研究试图填补部分文献空白。本文介绍了为确定暴露在实际沿海和内陆地区一年的 TMT、高铬钢 (CRS) 和不锈钢螺纹钢的腐蚀速率而进行的实验研究。研究地点位于印度泰米尔纳德邦东南部。在第一年腐蚀率的基础上，根据 ISO 9224 建议确定了长期暴露（10 年）后的腐蚀率。使用反距离插值技术绘制了泰米尔纳德邦大气钢腐蚀图。微观结构研究表明，在沿海地区采集的锈蚀产物中形成了鳞片钙钛矿（γ-FeOOH）相组成。
{"title":"MAPPING OF ATMOSPHERIC CORROSION OF STEEL IN SOUTHEAST INDIA USING INVERSE DISTANCE INTERPOLATION TECHNIQUE","authors":"J. Daniel Ronald Joseph, M. Ashok","doi":"10.5006/4535","DOIUrl":"https://doi.org/10.5006/4535","url":null,"abstract":"\u0000 Reinforced concrete and steel structural elements undergo premature degradation and lose strength primarily due to corrosion. Corrosion is an electrochemical phenomenon and its severity depends on number of environmental factors. Experimental data on corrosion of steel is important for making engineering decisions towards improving the service life of civil infrastructures. No recent dataset on atmospheric steel corrosion under Indian coastal environment is found to be available in the literature, and hence this research attempts to address some of the literature gap. This paper presents experimental study conducted to determine the corrosion rate of TMT, high-chromium steel (CRS) and stainless steel rebars exposed in actual coastal and inland regions for a period of one year. The site locations were located in southeastern parts of Tamilnadu state in India. Based on the first-year corrosion rate, the corrosion rate after extended exposure (10-years) was determined based on ISO 9224 recommendations. Atmospheric steel corrosion map of Tamilnadu state was developed using inverse distance interpolation technique. Microstructural studies indicated the formation of lepidocrocite (γ-FeOOH) phase composition in the rust products collected from coastal region.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141113129","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}
Jeong-Min Lim, Byung-Su Kim, Seung-Ho Ann, Jung-Gu Kim
In this study, the galvanic corrosion behavior of a tinned Cu terminal coupled with an Al–Mg–Si alloy was analyzed. When the Al alloy and tinned Cu were electrically connected and exposed to an electrolyte, tri–metallic galvanic corrosion occurred between the Al alloy, the Sn plating, and the Cu base metal. Results from Potentiodynamic and zero resistance ammeter tests indicate that the total galvanic corrosion rate increases as the area ratio of Sn plating to the Cu base metal decreases. Furthermore, the Sn, which has an intermediate potential, may function as either an anode or a cathode. While most of the Sn plating was protected by the Al alloy, corrosion of the Sn plating was observed at the boundary between the Sn plating and the Cu base metal. Thus, the exposed Cu area and galvanic corrosion of the Al-tinned Cu couple increase over time. Consequently, to prevent failure due to corrosion at the connection of the Al body and the tinned Cu terminal, exposed Cu area and damage of the Sn plating of tinned Cu terminal should be minimized.
{"title":"Galvanic Corrosion of Tinned Copper Coupled with Aluminium Alloy in Electric Vehicle","authors":"Jeong-Min Lim, Byung-Su Kim, Seung-Ho Ann, Jung-Gu Kim","doi":"10.5006/4478","DOIUrl":"https://doi.org/10.5006/4478","url":null,"abstract":"\u0000 In this study, the galvanic corrosion behavior of a tinned Cu terminal coupled with an Al–Mg–Si alloy was analyzed. When the Al alloy and tinned Cu were electrically connected and exposed to an electrolyte, tri–metallic galvanic corrosion occurred between the Al alloy, the Sn plating, and the Cu base metal. Results from Potentiodynamic and zero resistance ammeter tests indicate that the total galvanic corrosion rate increases as the area ratio of Sn plating to the Cu base metal decreases. Furthermore, the Sn, which has an intermediate potential, may function as either an anode or a cathode. While most of the Sn plating was protected by the Al alloy, corrosion of the Sn plating was observed at the boundary between the Sn plating and the Cu base metal. Thus, the exposed Cu area and galvanic corrosion of the Al-tinned Cu couple increase over time. Consequently, to prevent failure due to corrosion at the connection of the Al body and the tinned Cu terminal, exposed Cu area and damage of the Sn plating of tinned Cu terminal should be minimized.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141126363","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}
Xiaoqian Liu, Tieming Guo, Wan Zhang, Weihong Wu, Xueli Nan, Yanwen Hu, Xiangbin Yi
The corrosion behavior of Q420qNH steel plate and welded joint in deicing salt medium is investigated by cyclic immersion + infrared drying accelerated corrosion experiments. The results show that the corrosion products are mainly Fe2O3 and FeOCl under the influence of Cl- concentration differential corrosion microcells in the immersion corrosion anoxic stage, and the corrosion products are mainly β-FeOOH, γ-FeOOH, and Fe3O4 under the influence of oxygen concentration differential corrosion microcells catalyzed in the infrared drying stage. Throughout the corrosion process, the corrosion weight gain and average corrosion rate of the welded sample is always lower than that of the plate sample. The Iα-FeooH/Iβ-FeooH + FeOCl peak intensity ratio of the welded sample is always higher than that of the plate sample and the heat- affected zone sample. The corrosion types of the three samples are inhomogeneous total corrosion + pitting, and the depth of the pits in the plate is much larger than that in the weld and the heat-affected zone. In the late stage of corrosion, the self-corrosion current density is: plate > heat-affected zone > weld, and the resistance of the rust layer of the weld and heat-affected zone samples is 1.66 times and 1.31 times of that of the plate sample, respectively. This is because the microstructure of the weld and heat-affected zone are composed of a large number of fine acicular ferrite and lath-shaped bainite generated inside the original austenite grains, and the small angle grain boundary is not conducive to the initiation and expansion of pitting corrosion. In addition, the higher content of Cu, Cr, Ni and other elements in the weld can refine the rust layer products and effectively impede the intrusion of Cl-, contributing to the improvement of corrosion resistance. As the combined effect of Cl- and immersion anoxic environment inhibits the formation of α-FeOOH and promotes the formation of the large number of loose and unstable β-FeOOH and soluble FeOCl, the weathering steel is not well protected by the rust layer during cyclic immersion corrosion in deicing salt medium.
{"title":"Corrosion behavior of Q420qNH plate and welded joint in deicing salt medium by cyclic immersion + infrared drying","authors":"Xiaoqian Liu, Tieming Guo, Wan Zhang, Weihong Wu, Xueli Nan, Yanwen Hu, Xiangbin Yi","doi":"10.5006/4513","DOIUrl":"https://doi.org/10.5006/4513","url":null,"abstract":"\u0000 The corrosion behavior of Q420qNH steel plate and welded joint in deicing salt medium is investigated by cyclic immersion + infrared drying accelerated corrosion experiments. The results show that the corrosion products are mainly Fe2O3 and FeOCl under the influence of Cl- concentration differential corrosion microcells in the immersion corrosion anoxic stage, and the corrosion products are mainly β-FeOOH, γ-FeOOH, and Fe3O4 under the influence of oxygen concentration differential corrosion microcells catalyzed in the infrared drying stage. Throughout the corrosion process, the corrosion weight gain and average corrosion rate of the welded sample is always lower than that of the plate sample. The Iα-FeooH/Iβ-FeooH + FeOCl peak intensity ratio of the welded sample is always higher than that of the plate sample and the heat- affected zone sample. The corrosion types of the three samples are inhomogeneous total corrosion + pitting, and the depth of the pits in the plate is much larger than that in the weld and the heat-affected zone. In the late stage of corrosion, the self-corrosion current density is: plate > heat-affected zone > weld, and the resistance of the rust layer of the weld and heat-affected zone samples is 1.66 times and 1.31 times of that of the plate sample, respectively. This is because the microstructure of the weld and heat-affected zone are composed of a large number of fine acicular ferrite and lath-shaped bainite generated inside the original austenite grains, and the small angle grain boundary is not conducive to the initiation and expansion of pitting corrosion. In addition, the higher content of Cu, Cr, Ni and other elements in the weld can refine the rust layer products and effectively impede the intrusion of Cl-, contributing to the improvement of corrosion resistance. As the combined effect of Cl- and immersion anoxic environment inhibits the formation of α-FeOOH and promotes the formation of the large number of loose and unstable β-FeOOH and soluble FeOCl, the weathering steel is not well protected by the rust layer during cyclic immersion corrosion in deicing salt medium.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140968321","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}
N. Moradighadi, Huiru Wang, Luntao Wang, A. Seyeux, Alain Pailleret, Philippe Marcus, S. Nešić
Aqueous CO2 corrosion of mild steel is one of the major problems in the oil and gas industry. While current understanding primarily focuses on cathodic reaction mechanisms, less attention has been given to the impact of aqueous CO2 on the anodic iron dissolution reaction. In contrast, the mechanism of iron dissolution in strong acidic environments has been thoroughly investigated. Among the reaction mechanisms found in the open literature, a multi-path mechanism was identified that could explain the iron dissolution in strong acidic sulfate solution; both in terms of steady state polarization sweeps and impedance data at various pH values and current densities. However, the role of aqueous CO2 in solutions containing chlorides on the mechanism of iron dissolution had remained an open question. The present study used electrochemical impedance spectroscopy (EIS) as the main technique, to study the mechanism of iron dissolution in strong acid chloride solution with and without the presence of CO2. Results showed that the presence of chloride ions (0.5 M) decreases the rate of iron dissolution by competing with hydroxide ions to adsorb on the metal surface, forming chloride-containing intermediate species that participate in the iron dissolution reaction. The resulting decrease in the availability of hydroxide intermediates, which are more effective at enhancing the reaction rate compared to chloride-containing intermediates, leads to an overall decrease in the rate of iron dissolution. While the presence of CO2 increases anodic current density, EIS investigation revealed that neither aqueous CO2 nor other carbonic species directly react on the bare metal surface to form adsorbed intermediates involved in the anodic reaction. EIS investigation suggested that aqueous CO2 may induce changes in the chemical composition of adsorbed species, rate constants, and surface coverage, thereby altering the kinetics of the underlying reactions.
二氧化碳水溶液对低碳钢的腐蚀是石油和天然气行业的主要问题之一。目前的认识主要集中在阴极反应机制上，而较少关注二氧化碳水溶液对阳极铁溶解反应的影响。相反，在强酸性环境中铁溶解的机理已经得到了深入研究。在公开文献中发现的反应机理中，有一种多路径机理可以解释强酸性硫酸盐溶液中的铁溶解；无论是从稳态极化扫描还是从不同 pH 值和电流密度下的阻抗数据来看，都是如此。然而，含氯化物溶液中的二氧化碳水溶液对铁溶解机理的作用仍是一个未决问题。本研究以电化学阻抗谱（EIS）为主要技术，研究了二氧化碳存在和不存在的强酸氯化物溶液中铁的溶解机理。结果表明，氯离子（0.5 M）的存在会降低铁的溶解速率，因为氯离子会与氢氧根离子竞争吸附在金属表面，形成含氯化物的中间物质，参与铁的溶解反应。与含氯中间体相比，氢氧化中间体能更有效地提高反应速率，氢氧化中间体的减少导致铁溶解速率总体下降。虽然二氧化碳的存在会增加阳极电流密度，但 EIS 调查显示，水溶液中的二氧化碳或其他碳化物都不会直接在裸金属表面发生反应，形成参与阳极反应的吸附中间产物。EIS 研究表明，二氧化碳水溶液可能会导致吸附物种的化学成分、速率常数和表面覆盖率发生变化，从而改变基本反应的动力学。
{"title":"Investigation of iron dissolution mechanism in acidic solutions with and without dissolved CO2 – Part I: EIS measurements","authors":"N. Moradighadi, Huiru Wang, Luntao Wang, A. Seyeux, Alain Pailleret, Philippe Marcus, S. Nešić","doi":"10.5006/4511","DOIUrl":"https://doi.org/10.5006/4511","url":null,"abstract":"\u0000 Aqueous CO2 corrosion of mild steel is one of the major problems in the oil and gas industry. While current understanding primarily focuses on cathodic reaction mechanisms, less attention has been given to the impact of aqueous CO2 on the anodic iron dissolution reaction. In contrast, the mechanism of iron dissolution in strong acidic environments has been thoroughly investigated. Among the reaction mechanisms found in the open literature, a multi-path mechanism was identified that could explain the iron dissolution in strong acidic sulfate solution; both in terms of steady state polarization sweeps and impedance data at various pH values and current densities. However, the role of aqueous CO2 in solutions containing chlorides on the mechanism of iron dissolution had remained an open question. The present study used electrochemical impedance spectroscopy (EIS) as the main technique, to study the mechanism of iron dissolution in strong acid chloride solution with and without the presence of CO2. Results showed that the presence of chloride ions (0.5 M) decreases the rate of iron dissolution by competing with hydroxide ions to adsorb on the metal surface, forming chloride-containing intermediate species that participate in the iron dissolution reaction. The resulting decrease in the availability of hydroxide intermediates, which are more effective at enhancing the reaction rate compared to chloride-containing intermediates, leads to an overall decrease in the rate of iron dissolution. While the presence of CO2 increases anodic current density, EIS investigation revealed that neither aqueous CO2 nor other carbonic species directly react on the bare metal surface to form adsorbed intermediates involved in the anodic reaction. EIS investigation suggested that aqueous CO2 may induce changes in the chemical composition of adsorbed species, rate constants, and surface coverage, thereby altering the kinetics of the underlying reactions.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140998487","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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