Pub Date : 2024-05-29DOI: 10.1038/s41529-024-00457-7
Jaewoo Park, Amanda Leong, Jinsuo Zhang
The purification of salt is indispensable for mitigating the corrosion of structural materials for molten salt reactors or other molten salt applications. This study develops a salt-purification system to synthesize and purify NaF-KF-UF4 salt (FUNaK) using Ar purging and hydrofluorination of impurities. Chronoamperometry is also used to remove metallic impurities in the hydrofluorinated FUNaK. This purified FUNaK is then used for a static corrosion test of stainless steel 316H (SS316H) to study the effectiveness of salt purification in mitigating its corrosion. For comparison, results from a previous study about the corrosion of SS316H by thermally purified FUNaK are used. FUNaK with UF3 is also synthesized for a static corrosion test with the same condition to investigate the impact of UF3 on corrosion. The results show that the corrosion of SS316H is significantly reduced by using the chemically purified FUNaK compared to thermally purified FUNaK.
{"title":"Static corrosion of stainless steel 316H in chemically purified molten NaF-KF-UF4 salt","authors":"Jaewoo Park, Amanda Leong, Jinsuo Zhang","doi":"10.1038/s41529-024-00457-7","DOIUrl":"10.1038/s41529-024-00457-7","url":null,"abstract":"The purification of salt is indispensable for mitigating the corrosion of structural materials for molten salt reactors or other molten salt applications. This study develops a salt-purification system to synthesize and purify NaF-KF-UF4 salt (FUNaK) using Ar purging and hydrofluorination of impurities. Chronoamperometry is also used to remove metallic impurities in the hydrofluorinated FUNaK. This purified FUNaK is then used for a static corrosion test of stainless steel 316H (SS316H) to study the effectiveness of salt purification in mitigating its corrosion. For comparison, results from a previous study about the corrosion of SS316H by thermally purified FUNaK are used. FUNaK with UF3 is also synthesized for a static corrosion test with the same condition to investigate the impact of UF3 on corrosion. The results show that the corrosion of SS316H is significantly reduced by using the chemically purified FUNaK compared to thermally purified FUNaK.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-10"},"PeriodicalIF":5.1,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00457-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141182305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-28DOI: 10.1038/s41529-024-00477-3
Jiajiao Wei, Ke Hou, Feng Yang, Zhipeng Chang, Ju Li, Yunliang Shao, Mengjia Li, Xiaomei Yu, Jinyou Zheng, Yutao Zhou, Yongpeng Yang, Dehai Ping, Yong Liu, Min Li, Songjie Li
The influence of hydrogen charging potentials on the hydrogen embrittlement susceptibility of R6 ultra-high strength mooring chain steel was investigated via constant potential hydrogen charging slow strain rate tensile tests combined with thermal desorption analysis. The results reveal that hydrogen charging leads to a 38.94% decrease in elongation, while the impact on tensile strength is relatively minor. Furthermore, the specimens experienced intergranular cracking at the critical potential of −1150 mV, with the size of the brittle region increasing as the negative charging potential becomes more negative. And, hydrogen atoms can cause local embrittlement of materials and increase KAM value.
通过恒电位充氢慢应变速率拉伸试验结合热脱附分析，研究了充氢电位对 R6 超高强度系泊链钢氢脆敏感性的影响。结果表明，充氢导致伸长率下降 38.94%，而对拉伸强度的影响相对较小。此外，试样在临界电位 -1150 mV 时出现晶间开裂，脆性区域的大小随着负充电电位的增加而增大。而且，氢原子会导致材料局部脆化并增加 KAM 值。
{"title":"Delayed fracture behavior of ultra-high-strength mooring chain steel evaluated by potentiostatic hydrogen-charging combined with SSRT","authors":"Jiajiao Wei, Ke Hou, Feng Yang, Zhipeng Chang, Ju Li, Yunliang Shao, Mengjia Li, Xiaomei Yu, Jinyou Zheng, Yutao Zhou, Yongpeng Yang, Dehai Ping, Yong Liu, Min Li, Songjie Li","doi":"10.1038/s41529-024-00477-3","DOIUrl":"10.1038/s41529-024-00477-3","url":null,"abstract":"The influence of hydrogen charging potentials on the hydrogen embrittlement susceptibility of R6 ultra-high strength mooring chain steel was investigated via constant potential hydrogen charging slow strain rate tensile tests combined with thermal desorption analysis. The results reveal that hydrogen charging leads to a 38.94% decrease in elongation, while the impact on tensile strength is relatively minor. Furthermore, the specimens experienced intergranular cracking at the critical potential of −1150 mV, with the size of the brittle region increasing as the negative charging potential becomes more negative. And, hydrogen atoms can cause local embrittlement of materials and increase KAM value.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-11"},"PeriodicalIF":5.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00477-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141165083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-28DOI: 10.1038/s41529-024-00467-5
Peter Rodič, Barbara Kapun, Ingrid Milošev
Aluminium cast alloy AlSi7Mg0.3 is a lightweight metal commonly used in automotive, aeronautical and mechanical applications. It has good corrosion resistance but, under harsh operative conditions, would benefit from additional protection. In this study, a corrosion-protective multilayer coating system for AlSi7Mg0.3 based on hexafluoro-zirconated trivalent chromium coating (Zr-CrCC) and polyacrylic/siloxane-silica (PEHA-SS) coating was developed. The Zr-CrCC was formed by immersion of the substrate in a commercial conversion bath (SurTec® 650). PEHA-SS synthesis was based on organic precursors (2-ethylhexyl acrylate and [3-(methacryloyloxy)propyl]trimethoxysilane) and an inorganic precursor, tetraethyl orthosilicate. After deposition on AlSi7Mg0.3, each coating was first characterised individually, followed by the analysis of the multilayer using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adhesion of the coatings was evaluated with a cross-hatch cut test. The corrosion studies in sodium chloride solution using electrochemical impedance spectroscopy and salt spray testing showed that the multilayer system is superior to individual Zr-CrCC and PEHA-SS coatings. After 4 months in 0.1 M NaCl, the multilayer-coated samples exhibited the impedance at 10 mHz in the range of GΩ cm2, while scribed samples withstood the corrosion attack in a salt spray chamber for one week. Thus, albeit only about 100 nm thick, the Zr-CrCC deposited between the substrate and a 9-micrometre thick barrier sol-gel PEHA-SS coating acts as an active corrosion protection interlayer and contributes to the overall protectiveness of the multilayer system.
{"title":"Complementary corrosion protection of cast AlSi7Mg0.3 alloy using Zr-Cr conversion and polyacrylic/siloxane-silica multilayer coatings","authors":"Peter Rodič, Barbara Kapun, Ingrid Milošev","doi":"10.1038/s41529-024-00467-5","DOIUrl":"10.1038/s41529-024-00467-5","url":null,"abstract":"Aluminium cast alloy AlSi7Mg0.3 is a lightweight metal commonly used in automotive, aeronautical and mechanical applications. It has good corrosion resistance but, under harsh operative conditions, would benefit from additional protection. In this study, a corrosion-protective multilayer coating system for AlSi7Mg0.3 based on hexafluoro-zirconated trivalent chromium coating (Zr-CrCC) and polyacrylic/siloxane-silica (PEHA-SS) coating was developed. The Zr-CrCC was formed by immersion of the substrate in a commercial conversion bath (SurTec® 650). PEHA-SS synthesis was based on organic precursors (2-ethylhexyl acrylate and [3-(methacryloyloxy)propyl]trimethoxysilane) and an inorganic precursor, tetraethyl orthosilicate. After deposition on AlSi7Mg0.3, each coating was first characterised individually, followed by the analysis of the multilayer using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adhesion of the coatings was evaluated with a cross-hatch cut test. The corrosion studies in sodium chloride solution using electrochemical impedance spectroscopy and salt spray testing showed that the multilayer system is superior to individual Zr-CrCC and PEHA-SS coatings. After 4 months in 0.1 M NaCl, the multilayer-coated samples exhibited the impedance at 10 mHz in the range of GΩ cm2, while scribed samples withstood the corrosion attack in a salt spray chamber for one week. Thus, albeit only about 100 nm thick, the Zr-CrCC deposited between the substrate and a 9-micrometre thick barrier sol-gel PEHA-SS coating acts as an active corrosion protection interlayer and contributes to the overall protectiveness of the multilayer system.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-16"},"PeriodicalIF":5.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00467-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141165079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-25DOI: 10.1038/s41529-024-00475-5
Thomas L. Goût, Anamul H. Mir, Simon M. Fairclough, Dimitri Pletser, Ian Farnan
Zirconolite ceramics present a chemically durable host matrix for waste actinides, but zirconolite dissolution rates reported in the literature often vary significantly. Here, the release of Ca and Al from a hot isostatically pressed zirconolite (Ca0.8Zr0.9Ce0.3Ti1.6Al0.4O7.0) was shown to be predominantly driven by preferential dissolution of minor perovskite and alumina phases. Both phases were undetectable by XRD, and the perovskite was difficult to detect by SEM-EDS. Whilst the zirconolite phase exhibited no signs of alteration, dissolution of the perovskite proceeded congruently without forming a hydrated altered layer or diffusion of protons into the solid that would be indicative of an ion-exchange mechanism. The weak temperature dependence of dissolution (40, 90 and 150 °C) showed that kinetics were limited by transport and a mixed transport-surface controlled reaction for Ca and Al, respectively. A significant H2O-D2O isotope effect on dissolution was observed for Ca but not for Al at all temperatures. The former was consistent with an abated rate of hydrolysis in the absence of a contribution from diffusion, whilst the latter could be attributed to differences in the activated complex for Ca and Al release through hydrolysis. These results demonstrate the role of a secondary phase perovskite in the dissolution kinetics of zirconolite even when perovskite occurs at low concentration and evades detection by bulk techniques such as XRD. This study provides a potential explanation of variations in zirconolite ceramic dissolution rates present in the literature and provides a null result to tests of an incongruent Ca release mechanism from zirconolite.
{"title":"Undetected perovskite phase interference with zirconolite dissolution measurements","authors":"Thomas L. Goût, Anamul H. Mir, Simon M. Fairclough, Dimitri Pletser, Ian Farnan","doi":"10.1038/s41529-024-00475-5","DOIUrl":"10.1038/s41529-024-00475-5","url":null,"abstract":"Zirconolite ceramics present a chemically durable host matrix for waste actinides, but zirconolite dissolution rates reported in the literature often vary significantly. Here, the release of Ca and Al from a hot isostatically pressed zirconolite (Ca0.8Zr0.9Ce0.3Ti1.6Al0.4O7.0) was shown to be predominantly driven by preferential dissolution of minor perovskite and alumina phases. Both phases were undetectable by XRD, and the perovskite was difficult to detect by SEM-EDS. Whilst the zirconolite phase exhibited no signs of alteration, dissolution of the perovskite proceeded congruently without forming a hydrated altered layer or diffusion of protons into the solid that would be indicative of an ion-exchange mechanism. The weak temperature dependence of dissolution (40, 90 and 150 °C) showed that kinetics were limited by transport and a mixed transport-surface controlled reaction for Ca and Al, respectively. A significant H2O-D2O isotope effect on dissolution was observed for Ca but not for Al at all temperatures. The former was consistent with an abated rate of hydrolysis in the absence of a contribution from diffusion, whilst the latter could be attributed to differences in the activated complex for Ca and Al release through hydrolysis. These results demonstrate the role of a secondary phase perovskite in the dissolution kinetics of zirconolite even when perovskite occurs at low concentration and evades detection by bulk techniques such as XRD. This study provides a potential explanation of variations in zirconolite ceramic dissolution rates present in the literature and provides a null result to tests of an incongruent Ca release mechanism from zirconolite.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-16"},"PeriodicalIF":5.1,"publicationDate":"2024-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00475-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141149251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to make magnesium alloys better used in aviation, electronic information and other fields, it is necessary to improve their corrosion resistance and wave absorption properties. In this paper, a composite coating with corrosion resistance and wave absorption properties was prepared on magnesium alloy by micro-arc oxidation-organic coating technology. An organic absorbing coating with a thickness of about 40 μm was sprayed on the MAO coating containing Yb2O3 nanoparticles. Among them, the absorbing fillers in the organic coating are mainly SiO2 and α-Fe2O3. Three different mass ratios of SiO2 and α-Fe2O3 were set to 20%, 22.5% and 25%, respectively, to prepare three different MAO/SiO2@α-Fe2O3 organic composite coatings. The morphology, roughness, microstructure and chemical composition of the organic composite coating are characterized. The results show that after coating the organic composite coating, the roughness of the coating is significantly reduced, and the compactness and interlayer adhesion of the coating are significantly improved. The electrochemical test and SKPFM test of the organic composite coating were carried out. The results showed that with the increase of the mass ratio of SiO2 and α-Fe2O3, the corrosion resistance and stability of the organic composite coating increased, and the Volta potential also gradually moved up. The microwave absorbing properties of organic composite coatings were studied by vector network analyzer. The results show that the microwave absorbing properties of the coatings are positively correlated with the mass ratio of SiO2 and α-Fe2O3.
{"title":"Preparation and properties of Mg-Nd binary alloy MAO/SiO2@α-Fe2O3 organic composite coating","authors":"Qiang Sun, Quantong Jiang, Siwei Wu, Chang Liu, Heng Tang, Hao Shi, Liying Song, Jizhou Duan, Baorong Hou","doi":"10.1038/s41529-024-00473-7","DOIUrl":"10.1038/s41529-024-00473-7","url":null,"abstract":"In order to make magnesium alloys better used in aviation, electronic information and other fields, it is necessary to improve their corrosion resistance and wave absorption properties. In this paper, a composite coating with corrosion resistance and wave absorption properties was prepared on magnesium alloy by micro-arc oxidation-organic coating technology. An organic absorbing coating with a thickness of about 40 μm was sprayed on the MAO coating containing Yb2O3 nanoparticles. Among them, the absorbing fillers in the organic coating are mainly SiO2 and α-Fe2O3. Three different mass ratios of SiO2 and α-Fe2O3 were set to 20%, 22.5% and 25%, respectively, to prepare three different MAO/SiO2@α-Fe2O3 organic composite coatings. The morphology, roughness, microstructure and chemical composition of the organic composite coating are characterized. The results show that after coating the organic composite coating, the roughness of the coating is significantly reduced, and the compactness and interlayer adhesion of the coating are significantly improved. The electrochemical test and SKPFM test of the organic composite coating were carried out. The results showed that with the increase of the mass ratio of SiO2 and α-Fe2O3, the corrosion resistance and stability of the organic composite coating increased, and the Volta potential also gradually moved up. The microwave absorbing properties of organic composite coatings were studied by vector network analyzer. The results show that the microwave absorbing properties of the coatings are positively correlated with the mass ratio of SiO2 and α-Fe2O3.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-13"},"PeriodicalIF":5.1,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00473-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141103241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-21DOI: 10.1038/s41529-024-00476-4
Aditya Venkatraman, Ryan Michael Katona, Demitri Maestas, Matthew Roop, Philip Noell, David Montes de Oca Zapiain
The current present in a galvanic couple can define its resistance or susceptibility to corrosion. However, as the current is dependent upon environmental, material, and geometrical parameters it is experimentally costly to measure. To reduce these costs, Finite Element (FE) simulations can be used to assess the cathodic current but also require experimental inputs to define boundary conditions. Due to these challenges, it is crucial to accelerate predictions and accurately predict the current output for different environments and geometries representative of in-service conditions. Machine learned surrogate models provides a means to accelerate corrosion predictions. However, a one-time cost is incurred in procuring the simulation and experimental dataset necessary to calibrate the surrogate model. Therefore, an active learning protocol is developed through calibration of a low-cost surrogate model for the cathodic current of an exemplar galvanic couple (AA7075-SS304) as a function of environmental and geometric parameters. The surrogate model is calibrated on a dataset of FE simulations, and calculates an acquisition function that identifies specific additional inputs with the maximum potential to improve the current predictions. This is accomplished through a staggered workflow that not only improves and refines prediction, but identifies the points at which the most information is gained, thus enabling expansion to a larger parameter space. The protocols developed and demonstrated in this work provide a powerful tool for screening various forms of corrosion under in-service conditions.
电偶中的电流可以确定其电阻或易腐蚀性。然而，由于电流取决于环境、材料和几何参数，因此测量的实验成本很高。为了降低成本，可以使用有限元（FE）模拟来评估阴极电流，但也需要实验输入来定义边界条件。由于这些挑战，加速预测并准确预测不同环境下的电流输出以及代表在役条件的几何形状至关重要。机器学习代用模型为加速腐蚀预测提供了一种方法。然而，购买校准代用模型所需的模拟和实验数据集会产生一次性成本。因此，我们开发了一种主动学习协议，通过校准低成本的代理模型，将示范电偶（AA7075-SS304）的阴极电流作为环境和几何参数的函数。代用模型在 FE 模拟数据集上进行校准，并计算出一个获取函数，该函数可识别出具有最大潜力改进电流预测的特定额外输入。这是通过一个交错的工作流程实现的，该流程不仅能改进和完善预测，还能确定获得最多信息的点，从而扩展到更大的参数空间。这项工作中开发和演示的规程为在役条件下筛查各种形式的腐蚀提供了一个强大的工具。
{"title":"An active learning framework for the rapid assessment of galvanic corrosion","authors":"Aditya Venkatraman, Ryan Michael Katona, Demitri Maestas, Matthew Roop, Philip Noell, David Montes de Oca Zapiain","doi":"10.1038/s41529-024-00476-4","DOIUrl":"10.1038/s41529-024-00476-4","url":null,"abstract":"The current present in a galvanic couple can define its resistance or susceptibility to corrosion. However, as the current is dependent upon environmental, material, and geometrical parameters it is experimentally costly to measure. To reduce these costs, Finite Element (FE) simulations can be used to assess the cathodic current but also require experimental inputs to define boundary conditions. Due to these challenges, it is crucial to accelerate predictions and accurately predict the current output for different environments and geometries representative of in-service conditions. Machine learned surrogate models provides a means to accelerate corrosion predictions. However, a one-time cost is incurred in procuring the simulation and experimental dataset necessary to calibrate the surrogate model. Therefore, an active learning protocol is developed through calibration of a low-cost surrogate model for the cathodic current of an exemplar galvanic couple (AA7075-SS304) as a function of environmental and geometric parameters. The surrogate model is calibrated on a dataset of FE simulations, and calculates an acquisition function that identifies specific additional inputs with the maximum potential to improve the current predictions. This is accomplished through a staggered workflow that not only improves and refines prediction, but identifies the points at which the most information is gained, thus enabling expansion to a larger parameter space. The protocols developed and demonstrated in this work provide a powerful tool for screening various forms of corrosion under in-service conditions.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-11"},"PeriodicalIF":5.1,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00476-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Short-time oxidation behavior of nanocrystalline Ta coating is studied at 850 °C in comparison with that of the Ta sheet. Owing to the large PBR value and insufficient expansion space, the oxide scale on Ta sheet is dramatically cracked, delaminated and pulverized, resulting in rapid deterioration. For nanocrystalline Ta coatings with columnar structures and quantitative grain boundaries, a rapid oxygen diffusion rate causes no initial Ta2O5 to form. The gap between columns provides spaces for bulk expansion, resulting in few opening cracks and delamination. Ta oxidation experiences a crystallization course from amorphous Ta oxide, leading to in situ temperature surging and thus pulverization.
研究了纳米晶 Ta 涂层在 850 ℃ 下的短时氧化行为，并与 Ta 板的短时氧化行为进行了比较。由于 PBR 值较大且膨胀空间不足，Ta 片上的氧化鳞片出现了明显的裂纹、分层和粉化，从而导致快速劣化。对于具有柱状结构和定量晶界的纳米晶 Ta 涂层，快速的氧扩散速度不会形成初始的 Ta2O5。柱状结构之间的间隙为体积膨胀提供了空间，因此很少出现开口裂纹和分层。Ta 氧化经历了从无定形 Ta 氧化物结晶的过程，导致原位温度骤升，进而粉碎。
{"title":"Short-time high-temperature oxidation behavior of nanocrystalline Ta coating at 850 °C","authors":"Yunsong Niu, Lingling Xing, Shenglong Zhu, Jinfeng Huang, Minghui Chen, Fuhui Wang, Qiang Chen","doi":"10.1038/s41529-024-00465-7","DOIUrl":"10.1038/s41529-024-00465-7","url":null,"abstract":"Short-time oxidation behavior of nanocrystalline Ta coating is studied at 850 °C in comparison with that of the Ta sheet. Owing to the large PBR value and insufficient expansion space, the oxide scale on Ta sheet is dramatically cracked, delaminated and pulverized, resulting in rapid deterioration. For nanocrystalline Ta coatings with columnar structures and quantitative grain boundaries, a rapid oxygen diffusion rate causes no initial Ta2O5 to form. The gap between columns provides spaces for bulk expansion, resulting in few opening cracks and delamination. Ta oxidation experiences a crystallization course from amorphous Ta oxide, leading to in situ temperature surging and thus pulverization.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-9"},"PeriodicalIF":5.1,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00465-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140962311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-14DOI: 10.1038/s41529-024-00461-x
Priyanka Adapala, Thomas Avey, Yudie Yuan, Mary Lyn Lim, Ganesh Bhaskaran, Sazol Das, Alan Luo, Gerald S. Frankel
The corrosion performance of 6xxx series Al alloys has been found to depend on small changes in composition and microstructure. The corrosion behaviors of three aluminum alloys, AA6111, AA6451, and AA6016, were investigated. AA6111, containing primarily α (Al15 (Fe,Mn)3Si2) intermetallic particles (IMPs), and AA6016, containing primarily β (Al8Fe2Si) IMPs, exhibited the best and the worst overall corrosion performances, respectively, as indicated by the extent of corrosion in exposure tests. However, this ranking was not predicted by the standard interpretation of potentiodynamic polarization curves measured on the alloys. The corrosion susceptibilities of the three alloys were further investigated by evaluating the electrochemical behavior of the component phases separately. Bulk analogs of the component phases were fabricated using standard alloy casting techniques. The fabricated bulk analogs of α and β IMPs, as well as the three alloy matrix phases, were tested using either macrocell or microcell testing. An explanation for the alloy performances was developed by combining the behavior of the component phases.
{"title":"Understanding the effect of microstructure and composition on localized corrosion susceptibility of 6xxx aluminum alloys","authors":"Priyanka Adapala, Thomas Avey, Yudie Yuan, Mary Lyn Lim, Ganesh Bhaskaran, Sazol Das, Alan Luo, Gerald S. Frankel","doi":"10.1038/s41529-024-00461-x","DOIUrl":"10.1038/s41529-024-00461-x","url":null,"abstract":"The corrosion performance of 6xxx series Al alloys has been found to depend on small changes in composition and microstructure. The corrosion behaviors of three aluminum alloys, AA6111, AA6451, and AA6016, were investigated. AA6111, containing primarily α (Al15 (Fe,Mn)3Si2) intermetallic particles (IMPs), and AA6016, containing primarily β (Al8Fe2Si) IMPs, exhibited the best and the worst overall corrosion performances, respectively, as indicated by the extent of corrosion in exposure tests. However, this ranking was not predicted by the standard interpretation of potentiodynamic polarization curves measured on the alloys. The corrosion susceptibilities of the three alloys were further investigated by evaluating the electrochemical behavior of the component phases separately. Bulk analogs of the component phases were fabricated using standard alloy casting techniques. The fabricated bulk analogs of α and β IMPs, as well as the three alloy matrix phases, were tested using either macrocell or microcell testing. An explanation for the alloy performances was developed by combining the behavior of the component phases.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-12"},"PeriodicalIF":5.1,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00461-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140924940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-11DOI: 10.1038/s41529-024-00471-9
Leandro Vaccari, Thomas Scheithauer, Ivan Lendiel, Jan Klett, Thomas Hassel, Hans Jürgen Maier
Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.
{"title":"Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding","authors":"Leandro Vaccari, Thomas Scheithauer, Ivan Lendiel, Jan Klett, Thomas Hassel, Hans Jürgen Maier","doi":"10.1038/s41529-024-00471-9","DOIUrl":"10.1038/s41529-024-00471-9","url":null,"abstract":"Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-11"},"PeriodicalIF":5.1,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00471-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140907144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the passivation and localized corrosion of selective laser melted (SLM) stainless steel 316 L when exposed to high pressures of CO2 with the presence of H2S and Cl− at 25 °C and 125 °C were studied. Depletion of Cr/Mo was observed at the cell interiors and melt-pool boundaries (MPBs) compared to the cell boundaries. Volta potential differences obtained from scanning Kelvin probe force microscopy (SKPFM) showed that the MPBs were 8–20 mV lower than the matrix, while the cell interiors were 20–50 mV lower than the cell boundaries. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky tests indicated a more defective passive film at 125 °C, and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a less protective film with an increased S/O ratio at 125 °C than 25 °C. Initiation of localized corrosion was observed at the MPBs and pits formed after a week of immersion were wider by an order of magnitude at 125 °C than 25 °C, with evidence of cell-interior dissolution. While passivity was observed even at elevated temperatures, local chemical heterogeneities compromised the stability of the film and contributed to localized corrosion in SLM SS316L.
在这项工作中，研究了选择性激光熔化（SLM）不锈钢 316 L 在 25 °C 和 125 °C 下暴露于存在 H2S 和 Cl- 的高压 CO2 时的钝化和局部腐蚀情况。与晶胞边界相比，在晶胞内部和熔池边界 (MPB) 观察到了铬/钼的损耗。从扫描开尔文探针力显微镜（SKPFM）获得的伏特电位差显示，MPB 比基质低 8-20 mV，而电池内部比电池边界低 20-50 mV。电化学阻抗谱（EIS）和莫特-肖特基测试表明，125 °C时被动膜的缺陷更大，X射线光电子能谱（XPS）证实，125 °C时形成的保护膜比25 °C时的S/O比更小。在 MPB 上观察到局部腐蚀的开始，浸泡一周后形成的凹坑在 125 °C时比 25 °C时宽一个数量级，并有细胞内部溶解的证据。虽然即使在高温下也能观察到钝化现象，但局部化学异质性损害了薄膜的稳定性，并导致了 SLM SS316L 的局部腐蚀。
{"title":"Localized corrosion in selective laser melted SS316L in CO2 and H2S brines at elevated temperatures","authors":"Deeparekha Narayanan, Alan Martinez, Ulises Martin, Bilal Mansoor, Raymundo Case, Homero Castaneda","doi":"10.1038/s41529-024-00468-4","DOIUrl":"10.1038/s41529-024-00468-4","url":null,"abstract":"In this work, the passivation and localized corrosion of selective laser melted (SLM) stainless steel 316 L when exposed to high pressures of CO2 with the presence of H2S and Cl− at 25 °C and 125 °C were studied. Depletion of Cr/Mo was observed at the cell interiors and melt-pool boundaries (MPBs) compared to the cell boundaries. Volta potential differences obtained from scanning Kelvin probe force microscopy (SKPFM) showed that the MPBs were 8–20 mV lower than the matrix, while the cell interiors were 20–50 mV lower than the cell boundaries. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky tests indicated a more defective passive film at 125 °C, and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a less protective film with an increased S/O ratio at 125 °C than 25 °C. Initiation of localized corrosion was observed at the MPBs and pits formed after a week of immersion were wider by an order of magnitude at 125 °C than 25 °C, with evidence of cell-interior dissolution. While passivity was observed even at elevated temperatures, local chemical heterogeneities compromised the stability of the film and contributed to localized corrosion in SLM SS316L.","PeriodicalId":19270,"journal":{"name":"npj Materials Degradation","volume":" ","pages":"1-14"},"PeriodicalIF":5.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41529-024-00468-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140902849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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