ABSTRACT In this paper, the influence of mechanical torsion on corrosion of MgCa1 alloy in simulated body fluid (SBF) is presented. The corrosion behavior is examined by microstructural observations, including a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy detector (EDS) and electrochemical studies, mainly impedance spectroscopy measurements (EIS) and polarization curves (PC). The experiments were performed for different time durations (4-8 h) with and without torsion applied (within elastic deformation range in the form of rotary movements) to assign the differences between the corrosion behavior of the samples. It is shown that mechanical torsion (rotations) promotes the leaching of calcium from the grain boundaries in the samples, what decreases the overall alloy corrosion rate. On the other hand, grain boundaries leached out of calcium compounds influence the sample microstructure by enabling for cracks formation and propagation. Therefore, rotated samples corroded at a lower rate but were more susceptible to catastrophic failure. It was then concluded that MgCa1 alloy may be promising biodegradable material for medical implants, however, its durability in SBF with torsion applied is far from being satisfactory.
{"title":"Influence of mechanical torsion on MgCa1 corrosion behavior in SBF","authors":"Daria Serafin, Malwina Świderska, Joanna Klimek, Lech Kwiatkowski, Ryszard Sitek, Bartek Wierzba","doi":"10.5006/4312","DOIUrl":"https://doi.org/10.5006/4312","url":null,"abstract":"ABSTRACT In this paper, the influence of mechanical torsion on corrosion of MgCa1 alloy in simulated body fluid (SBF) is presented. The corrosion behavior is examined by microstructural observations, including a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy detector (EDS) and electrochemical studies, mainly impedance spectroscopy measurements (EIS) and polarization curves (PC). The experiments were performed for different time durations (4-8 h) with and without torsion applied (within elastic deformation range in the form of rotary movements) to assign the differences between the corrosion behavior of the samples. It is shown that mechanical torsion (rotations) promotes the leaching of calcium from the grain boundaries in the samples, what decreases the overall alloy corrosion rate. On the other hand, grain boundaries leached out of calcium compounds influence the sample microstructure by enabling for cracks formation and propagation. Therefore, rotated samples corroded at a lower rate but were more susceptible to catastrophic failure. It was then concluded that MgCa1 alloy may be promising biodegradable material for medical implants, however, its durability in SBF with torsion applied is far from being satisfactory.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135208050","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}
ABSTRACT Corrosion under insulation (CUI) is one of the increasing issues in industries especially oil refineries and petrochemical plants. For preventing the accident and reducing the inspection load caused by CUI, prediction model for CUI has attracted increasing attention. In this study, to construct prediction model for corrosion rate of CUI (CUI rate), the effects of water content in the insulation material, salinity, and temperature on the CUI rate were evaluated with a corrosion test simulating CUI environment. Analysis of the atmospheric corrosion monitoring sensor current showed that the CUI rate increased as the water content increased, promoting formation of the water thin film at the interface of insulation and carbon steel. Maxima of the CUI rate were observed for salinity and temperature. Salinity increased the electrical conductivity of the water thin film and promoted the corrosion reaction, and over a certain salinity, the water thin film became thicker and the CUI rate decreased due to the rate determining step in oxygen diffusion. Over a certain temperature, the CUI rate decreased due to evaporation of the water thin film and a decrease in dissolved oxygen. We constructed the prediction model for the CUI rate with a coefficient of determination of 0.87 by multiple regression analysis using the obtained test data.
{"title":"Empirical Model for Predicting Corrosion Under Insulation Considering the Effects of Temperature, Salinity, and Water Content","authors":"Hayate Saito, Masahiro Ito, Katsumi Mabuchi","doi":"10.5006/4359","DOIUrl":"https://doi.org/10.5006/4359","url":null,"abstract":"ABSTRACT Corrosion under insulation (CUI) is one of the increasing issues in industries especially oil refineries and petrochemical plants. For preventing the accident and reducing the inspection load caused by CUI, prediction model for CUI has attracted increasing attention. In this study, to construct prediction model for corrosion rate of CUI (CUI rate), the effects of water content in the insulation material, salinity, and temperature on the CUI rate were evaluated with a corrosion test simulating CUI environment. Analysis of the atmospheric corrosion monitoring sensor current showed that the CUI rate increased as the water content increased, promoting formation of the water thin film at the interface of insulation and carbon steel. Maxima of the CUI rate were observed for salinity and temperature. Salinity increased the electrical conductivity of the water thin film and promoted the corrosion reaction, and over a certain salinity, the water thin film became thicker and the CUI rate decreased due to the rate determining step in oxygen diffusion. Over a certain temperature, the CUI rate decreased due to evaporation of the water thin film and a decrease in dissolved oxygen. We constructed the prediction model for the CUI rate with a coefficient of determination of 0.87 by multiple regression analysis using the obtained test data.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135207302","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}
This perspective is intended to bring awareness to the corrosion community that the growing demand for engineering metallic materials required for our increasingly technological society is unsustainable. Current strategies important for materials science and especially the corrosion community are presented. First, the consumption of metals is reviewed, and the global supplies and demands of metals are discussed given different scenarios, including models of global societal development. It is pointed out that expected future consumption rates place pressure on the availability of specific elements used regularly throughout the world, with nearly every element in the periodic table now utilized in production of new technological devices. The consumption pushes the mining and production of metals to levels that should be counterbalanced with novel engineering and technological methods that incorporate strategies for metal sustainability. Standard approaches such as “make-use-dispose” must gradually be transformed into a circular economy paradigm embracing the “reduce-reuse-recycle” approach. Although recycling can bolster the engineered material supply, the growing demands require additional actions to significantly preserve natural resources and prolong metal sustainability. Our views on the abilities of the corrosion community to contribute to the concept of a circular sustainable economy are introduced. Maintenance strategies and corrosion management control may not be sufficient and need to be complemented with existing or emerging new technologies such as additive manufacturing, inverse engineering design, and solvometallurgy in combination with integrative design, modeling, and machine learning approaches. The corrosion community can impact the end-of-life of components and infrastructure at different levels, starting from mining through design, production, use, reuse, and recycling. Each process step is discussed, seeking possible solutions to preserve the metal resources by, for example, achieving more efficient and high-yield mining, designing and modeling new materials, increasing production efficiency, introducing light-weighting and smart materials, as well as developing more efficient recovery, recycling, and separation.
{"title":"Challenges for the Corrosion Science, Engineering, and Technology Community as a Consequence of Growing Demand and Consumption of Materials: A Sustainability Issue","authors":"I. Milošev, John R. Scully","doi":"10.5006/4428","DOIUrl":"https://doi.org/10.5006/4428","url":null,"abstract":"This perspective is intended to bring awareness to the corrosion community that the growing demand for engineering metallic materials required for our increasingly technological society is unsustainable. Current strategies important for materials science and especially the corrosion community are presented. First, the consumption of metals is reviewed, and the global supplies and demands of metals are discussed given different scenarios, including models of global societal development. It is pointed out that expected future consumption rates place pressure on the availability of specific elements used regularly throughout the world, with nearly every element in the periodic table now utilized in production of new technological devices. The consumption pushes the mining and production of metals to levels that should be counterbalanced with novel engineering and technological methods that incorporate strategies for metal sustainability. Standard approaches such as “make-use-dispose” must gradually be transformed into a circular economy paradigm embracing the “reduce-reuse-recycle” approach. Although recycling can bolster the engineered material supply, the growing demands require additional actions to significantly preserve natural resources and prolong metal sustainability. Our views on the abilities of the corrosion community to contribute to the concept of a circular sustainable economy are introduced. Maintenance strategies and corrosion management control may not be sufficient and need to be complemented with existing or emerging new technologies such as additive manufacturing, inverse engineering design, and solvometallurgy in combination with integrative design, modeling, and machine learning approaches. The corrosion community can impact the end-of-life of components and infrastructure at different levels, starting from mining through design, production, use, reuse, and recycling. Each process step is discussed, seeking possible solutions to preserve the metal resources by, for example, achieving more efficient and high-yield mining, designing and modeling new materials, increasing production efficiency, introducing light-weighting and smart materials, as well as developing more efficient recovery, recycling, and separation.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47787456","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}
Ferrous sulfate (FeSO4) treatment is a technique used to protect copper and its alloys against corrosion by promoting the formation of a protective surface film. However, the effectiveness of FeSO4 treatment is dependent on a number of parameters relating to how the treatment is applied. This article summarizes the various FeSO4 treatment parameters explored in prior studies, highlighting the significance of key parameters such as fluid flow, media replenishment, and media composition in treating copper-nickel (CuNi) alloys. Furthermore, a series of experiments are conducted to validate the impact of these critical parameters on the formation and composition of the protective film on treated alloys. The results obtained emphasize the importance of these parameters in achieving a successful FeSO4 treatment and improved corrosion resistance for CuNi alloys. Overall, this paper provides an overview of the various FeSO4 treatment parameters and how they affect the treatment outcome for CuNi alloys.
{"title":"On the use of ferrous sulfate treatment to enhance the corrosion resistance of copper-nickel alloys","authors":"M. A. Javed, W. Neil, S. Wade","doi":"10.5006/4378","DOIUrl":"https://doi.org/10.5006/4378","url":null,"abstract":"Ferrous sulfate (FeSO<sub>4</sub>) treatment is a technique used to protect copper and its alloys against corrosion by promoting the formation of a protective surface film. However, the effectiveness of FeSO<sub>4</sub> treatment is dependent on a number of parameters relating to how the treatment is applied. This article summarizes the various FeSO<sub>4</sub> treatment parameters explored in prior studies, highlighting the significance of key parameters such as fluid flow, media replenishment, and media composition in treating copper-nickel (CuNi) alloys. Furthermore, a series of experiments are conducted to validate the impact of these critical parameters on the formation and composition of the protective film on treated alloys. The results obtained emphasize the importance of these parameters in achieving a successful FeSO<sub>4</sub> treatment and improved corrosion resistance for CuNi alloys. Overall, this paper provides an overview of the various FeSO<sub>4</sub> treatment parameters and how they affect the treatment outcome for CuNi alloys.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42897078","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}
Surface finish or integrity is always an important problem threatening the safety service of components. In this study, the stress corrosion cracking (SCC) initiation behavior of Monel 400 alloy with different surface working treatments (mechanical grinding (TD specimen and PD specimen) and electrolytic polishing (EP specimen)) in hydrofluoric acid (HF) vapor were compared by conducting slow strain rate test (SSRT) and constant loading test (CLT). Although SSRT can evaluate the enhancement effect of mechanical grinding on SCC susceptibility, it cannot quantify its contribution to the crack initiation stage. The CLT shows the cracking initiation rate of different specimens in order of: EP specimen
{"title":"Detrimental Effect of Surface Mechanical Grinding on Stress Corrosion Behavior of Monel 400 alloy in Hydrofluoric Acid Vapor","authors":"Dai Hailong, S. Shi, C. Guo, Xinfa Chen","doi":"10.5006/4382","DOIUrl":"https://doi.org/10.5006/4382","url":null,"abstract":"Surface finish or integrity is always an important problem threatening the safety service of components. In this study, the stress corrosion cracking (SCC) initiation behavior of Monel 400 alloy with different surface working treatments (mechanical grinding (TD specimen and PD specimen) and electrolytic polishing (EP specimen)) in hydrofluoric acid (HF) vapor were compared by conducting slow strain rate test (SSRT) and constant loading test (CLT). Although SSRT can evaluate the enhancement effect of mechanical grinding on SCC susceptibility, it cannot quantify its contribution to the crack initiation stage. The CLT shows the cracking initiation rate of different specimens in order of: EP specimen<TD specimen<PD specimen. For mechanical grinding specimens, local corrosion and cracks are inclined to nucleate at the groove shoulder zone rather groove bottom, which is mainly ascribed to the accumulation of higher corrosion degradation and higher defects at the groove shoulder. As the shoulder edge on the PD specimen is less constrained, it is easier to induce cracking under the synergistic action of stress concentration and preferential corrosion dissolution. While, the shoulder edge of the TD specimen is not a stress concentration position under tensile loading, and the micro-cracks formed by grinding are parallel to the loading direction, which is not conducive to the development of micro-cracks. Therefore, the crack initiation sensitivity of the TD specimen is lower than that of the PD specimen.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45728858","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}
Mohammadhadi Motaghed, M. Behbahani-Nejad, M. Changizian
A single-level fast multipole boundary element method was developed for analyzing cathodic protection systems of large pipeline networks. This method was obtained by embedding far-field approximation within the traditional single-level fast multipole method. The far-field approximation was used for computing the coefficients for far elements within adjacent cells and determining the moments of the elements within far cells. This approximation reduced the difficulty of the procedures and programming leading to a significant decrease in CPU time. The Newton-Raphson method and GMRES were combined based on the proposed method to solve the nonlinear boundary conditions due to the polarization curve. Several cathodic protection problems were considered to verify and evaluate the method. The calculated potentials of this method were in good agreement with the conventional boundary element method, which was achieved by using pipe elements and quadrilateral elements to mesh the surfaces. Finally, the impressed current cathodic protection systems of a large network (more than 100,000 elements) and a complex urban gas network were investigated. The results indicated the capability, efficiency, and precision of the present method for solving large and complicated problems on a common desktop computer.
{"title":"The Accuracy and Efficiency of a Single-Level Fast Multipole Boundary Element Model for Analyzing Cathodic Protection of Large Pipeline Networks","authors":"Mohammadhadi Motaghed, M. Behbahani-Nejad, M. Changizian","doi":"10.5006/4329","DOIUrl":"https://doi.org/10.5006/4329","url":null,"abstract":"A single-level fast multipole boundary element method was developed for analyzing cathodic protection systems of large pipeline networks. This method was obtained by embedding far-field approximation within the traditional single-level fast multipole method. The far-field approximation was used for computing the coefficients for far elements within adjacent cells and determining the moments of the elements within far cells. This approximation reduced the difficulty of the procedures and programming leading to a significant decrease in CPU time. The Newton-Raphson method and GMRES were combined based on the proposed method to solve the nonlinear boundary conditions due to the polarization curve. Several cathodic protection problems were considered to verify and evaluate the method. The calculated potentials of this method were in good agreement with the conventional boundary element method, which was achieved by using pipe elements and quadrilateral elements to mesh the surfaces. Finally, the impressed current cathodic protection systems of a large network (more than 100,000 elements) and a complex urban gas network were investigated. The results indicated the capability, efficiency, and precision of the present method for solving large and complicated problems on a common desktop computer.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48809013","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}
Corrosion can lead to mechanical damage near the material surface and reduce the material strength. It is essential to understand and simulate corrosion damage evolution for predicting the residual service life of engineering structure, reliability analysis, and corrosion-resistant design of materials. Several major novel corrosion simulation methods in the past ten years are mainly introduced: cellular automata method, finite element method, phase field model and peridynamics model. The computational modeling of localized corrosion is discussed and the advantages and disadvantages are compared. Finally, some difficulties in practical engineering applications such as dynamic interface tracking, multi-scale and multi-physical field corrosion simulation, and standardization of corrosion simulation are proposed, and the future investigation direction is prospected. With the rapid development of software science and computer technology, the operation speed and accuracy of numerical simulation will be greatly improved. The application advantages of numerical simulation in the field of corrosion will be more prominent.
{"title":"Progress and Opportunities in Computational Modeling of Localized Corrosion","authors":"Yuanyang Miao, S. Lv, S. Tirumalai, Xiaosheng Gao","doi":"10.5006/4301","DOIUrl":"https://doi.org/10.5006/4301","url":null,"abstract":"Corrosion can lead to mechanical damage near the material surface and reduce the material strength. It is essential to understand and simulate corrosion damage evolution for predicting the residual service life of engineering structure, reliability analysis, and corrosion-resistant design of materials. Several major novel corrosion simulation methods in the past ten years are mainly introduced: cellular automata method, finite element method, phase field model and peridynamics model. The computational modeling of localized corrosion is discussed and the advantages and disadvantages are compared. Finally, some difficulties in practical engineering applications such as dynamic interface tracking, multi-scale and multi-physical field corrosion simulation, and standardization of corrosion simulation are proposed, and the future investigation direction is prospected. With the rapid development of software science and computer technology, the operation speed and accuracy of numerical simulation will be greatly improved. The application advantages of numerical simulation in the field of corrosion will be more prominent.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42745536","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 mathematical relationship between corrosion degree and time is referred to as corrosion model. Existing corrosion models can only be used to predict the corrosion wastage of a certain material based on its available historical corrosion data, but the corrosion wastage of newer steel grades cannot be obtained if the data are not available. To solve this problem, two advanced algorithms, i.e., Generalized Regression Neural Network (GRNN) and optimizing grey model (OGM (1, N)), are introduced, based on which corrosion models can be obtained for steel classes even in the absence of historical corrosion data, as long as the chemical compositions of the material are known. Firstly, the theoretical basis and operational procedures of GRNN and OGM (1, N) are introduced. Grey relational analysis of corrosion wastage influencing factors is subsequently conducted. Lastly, the time-dependent atmospheric corrosion wastages of Q345 and Q460 steels, two typical structural steel grades but their corrosion models have not been well established, are predicted based on their chemical compositions by these two advanced algorithms. The results show that the main chemical compositions that influence the atmospheric corrosion wastage of steels are C and S; Both GRNN and OGM (1, N) can accurately predict the corrosion wastage of the steels, and the predicted results can be fitted by quadratic function or power function, where the goodness of fit is greater than 0.95, which indicates a high fitting accuracy.
{"title":"Advanced algorithms to predict time-dependent atmospheric corrosion wastage of low-alloy and high-strength steels based on chemical compositions","authors":"zhang Zhang, Ruyan Zheng","doi":"10.5006/4363","DOIUrl":"https://doi.org/10.5006/4363","url":null,"abstract":"The mathematical relationship between corrosion degree and time is referred to as corrosion model. Existing corrosion models can only be used to predict the corrosion wastage of a certain material based on its available historical corrosion data, but the corrosion wastage of newer steel grades cannot be obtained if the data are not available. To solve this problem, two advanced algorithms, i.e., Generalized Regression Neural Network (GRNN) and optimizing grey model (OGM (1, N)), are introduced, based on which corrosion models can be obtained for steel classes even in the absence of historical corrosion data, as long as the chemical compositions of the material are known. Firstly, the theoretical basis and operational procedures of GRNN and OGM (1, N) are introduced. Grey relational analysis of corrosion wastage influencing factors is subsequently conducted. Lastly, the time-dependent atmospheric corrosion wastages of Q345 and Q460 steels, two typical structural steel grades but their corrosion models have not been well established, are predicted based on their chemical compositions by these two advanced algorithms. The results show that the main chemical compositions that influence the atmospheric corrosion wastage of steels are C and S; Both GRNN and OGM (1, N) can accurately predict the corrosion wastage of the steels, and the predicted results can be fitted by quadratic function or power function, where the goodness of fit is greater than 0.95, which indicates a high fitting accuracy.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44664669","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 second group of ‘state-of-the-art’ contributions [1-4] by invited researchers on the ‘Environment-Induced Crack Initiation and Early Stages of Crack Growth in Aluminum Alloys’ appear in this issue, complementing the papers published in the January 2023 issue of Corrosion [5-8]. The second section, presented herein, includes an overview of the experimental study of the initiation of environment-induced cracking (EIC) in aluminum alloys conducted since the 1950’s [1], showing crack initiation typically dominates the total life experienced during both service-life for structural applications and for smooth tensile test specimens subjected to conventional standard EIC testing. The review also reveals, although research conducted over the last 30 years almost exclusively focus on EIC propagation, there are notable exceptions worthy of re-evaluation and further study using modern in-situ advanced experimental techniques, paying particular attention to the roles of creep, crack-arrest and surface conditions during EIC initiation, paying particular attention the immediate sub-surface layers. The three additional papers in this collection are experimental studies. One investigates the significant differences in EIC initiation observed from fatigue pre-cracks and corrosion-induced fissures under controlled electrochemical conditions in a sensitized AA5456-H116 fracture mechanics test specimen exposed to a marine environment [2]. The final two papers involve testing conducted on high Zn-content Al-Zn-Mg-Cu 7xxx series alloys [3, 4]: one involves two commercial thick pate commercial high Zn content new-generation alloys [3], AA7449 and AA7085 in the T7651 temper and provides a detailed description of EIC initiation and its transition to long-crack growth during exposure to water vapor at 70 °C. Information gleaned from in-situ time-lapse, optical imaging over large areas has enabled the exact initiation sites to be identified and investigated with high-resolution fractographic studies. In the final paper [4] based on the deformation and fracture behavior of a high Zn-content Al-Zn-Mg-Cu 7xxx alloy observed in situ using synchrotron radiation X-ray tomography, it is proposed the dispersion of Mn-based second-phase particles may offer a novel approach for preventing hydrogen embrittlement in 7xxx series aluminum alloys.
{"title":"Editorial: Environment-Induced Crack Initiation and Early Stages of Crack Growth in Aluminum Alloys, Part 2","authors":"N. Holroyd, T. Burnett, G. Scamans","doi":"10.5006/4409","DOIUrl":"https://doi.org/10.5006/4409","url":null,"abstract":"A second group of ‘state-of-the-art’ contributions [1-4] by invited researchers on the ‘Environment-Induced Crack Initiation and Early Stages of Crack Growth in Aluminum Alloys’ appear in this issue, complementing the papers published in the January 2023 issue of Corrosion [5-8]. The second section, presented herein, includes an overview of the experimental study of the initiation of environment-induced cracking (EIC) in aluminum alloys conducted since the 1950’s [1], showing crack initiation typically dominates the total life experienced during both service-life for structural applications and for smooth tensile test specimens subjected to conventional standard EIC testing. The review also reveals, although research conducted over the last 30 years almost exclusively focus on EIC propagation, there are notable exceptions worthy of re-evaluation and further study using modern in-situ advanced experimental techniques, paying particular attention to the roles of creep, crack-arrest and surface conditions during EIC initiation, paying particular attention the immediate sub-surface layers. The three additional papers in this collection are experimental studies. One investigates the significant differences in EIC initiation observed from fatigue pre-cracks and corrosion-induced fissures under controlled electrochemical conditions in a sensitized AA5456-H116 fracture mechanics test specimen exposed to a marine environment [2]. The final two papers involve testing conducted on high Zn-content Al-Zn-Mg-Cu 7xxx series alloys [3, 4]: one involves two commercial thick pate commercial high Zn content new-generation alloys [3], AA7449 and AA7085 in the T7651 temper and provides a detailed description of EIC initiation and its transition to long-crack growth during exposure to water vapor at 70 °C. Information gleaned from in-situ time-lapse, optical imaging over large areas has enabled the exact initiation sites to be identified and investigated with high-resolution fractographic studies. In the final paper [4] based on the deformation and fracture behavior of a high Zn-content Al-Zn-Mg-Cu 7xxx alloy observed in situ using synchrotron radiation X-ray tomography, it is proposed the dispersion of Mn-based second-phase particles may offer a novel approach for preventing hydrogen embrittlement in 7xxx series aluminum alloys.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42570836","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}
This paper investigates the electrochemical characteristics of the 7B04 aluminum alloy/anodic film/epoxy coating system in a simulated marine atmosphere using electrochemical techniques and surface morphology measurements. The coating system underwent a periodic immersion test for 480 hours to simulate the harsh service conditions in a marine environment. Three equivalent circuit models were proposed based on the analysis of the electrochemical failure mechanism of the coating system. AIC (Akaike Information Criterion) and BIC (Bayesian Information Criterion) were used to selectively choose models for different degradation stages of the coating system, revealing its electrochemical degradation characteristics. Two-stage aging kinetics and Gamma models were proposed to describe the time-varying processes of electrochemical low-frequency impedance and corrosion trend, respectively. Ultimately, low-frequency impedance is identified as the most effective and rapid evaluation index for coating performance due to its strong correlation with corrosion trends. The aforementioned models and index provide a foundation for accurately identifying corrosion stages and effectively predicting the corrosion process.
本文利用电化学技术和表面形貌测量，研究了7B04铝合金/阳极膜/环氧涂层体系在模拟海洋大气中的电化学特性。涂层系统进行了480小时的周期性浸渍测试，以模拟海洋环境中的恶劣使用条件。在分析涂层体系电化学失效机理的基础上，提出了三种等效电路模型。采用AIC（Akaike Information Criterion）和BIC（Bayesian Information Criterium）对涂层体系不同降解阶段的模型进行了选择性选择，揭示了涂层体系的电化学降解特性。提出了两阶段老化动力学和Gamma模型，分别描述了电化学低频阻抗和腐蚀趋势的时变过程。最终，低频阻抗被确定为最有效、最快速的涂层性能评估指标，因为它与腐蚀趋势有很强的相关性。上述模型和指标为准确识别腐蚀阶段和有效预测腐蚀过程提供了基础。
{"title":"Electrochemical Study on Corrosion Damage of 7B04 Aluminum Alloy/Anodic Film/Epoxy Coating System in Simulated Marine Atmospheric Environment","authors":"H. Ji, Xiaobing Ma, Yikun Cai, Han Wang","doi":"10.5006/4380","DOIUrl":"https://doi.org/10.5006/4380","url":null,"abstract":"This paper investigates the electrochemical characteristics of the 7B04 aluminum alloy/anodic film/epoxy coating system in a simulated marine atmosphere using electrochemical techniques and surface morphology measurements. The coating system underwent a periodic immersion test for 480 hours to simulate the harsh service conditions in a marine environment. Three equivalent circuit models were proposed based on the analysis of the electrochemical failure mechanism of the coating system. AIC (Akaike Information Criterion) and BIC (Bayesian Information Criterion) were used to selectively choose models for different degradation stages of the coating system, revealing its electrochemical degradation characteristics. Two-stage aging kinetics and Gamma models were proposed to describe the time-varying processes of electrochemical low-frequency impedance and corrosion trend, respectively. Ultimately, low-frequency impedance is identified as the most effective and rapid evaluation index for coating performance due to its strong correlation with corrosion trends. The aforementioned models and index provide a foundation for accurately identifying corrosion stages and effectively predicting the corrosion process.","PeriodicalId":10717,"journal":{"name":"Corrosion","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43239365","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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