{"title":"Masthead: Materials and Corrosion. 06/2021","authors":"","doi":"10.1002/maco.202170062","DOIUrl":"https://doi.org/10.1002/maco.202170062","url":null,"abstract":"","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"157 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82643383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lili Wang, M. Ye, Yingying Wang, Dong Tian, Zuoyan Ye, Chao Wang
{"title":"Corrosion behavior of the nickel/nickel interface during the copper‐sacrificial layer release process in micro‐electroforming","authors":"Lili Wang, M. Ye, Yingying Wang, Dong Tian, Zuoyan Ye, Chao Wang","doi":"10.1002/maco.202112815","DOIUrl":"https://doi.org/10.1002/maco.202112815","url":null,"abstract":"This study investigates the corrosion behavior of the nickel/nickel (Ni/Ni) interface during the release of the copper‐sacrificial layer in multilayered micro‐electroforming. By altering the pre‐ and posttreatment of multilayered micro‐electroforming (degreasing, in situ anodic treatment, pickling, repassivation, and heat treatment), six different types of Ni/Ni interfaces were obtained. The activities and surface characteristics of the pretreated Ni substrates were investigated via open circuit potential and X‐ray photoelectron spectroscopy. The microstructures of the as‐prepared Ni/Ni interfaces were determined using scanning electron microscopy; after releasing the sacrificial layer in the ferric chloride solution, their corrosion morphologies and corrosion depths were observed under a three‐dimensional microscope with an ultra‐depth of field. The Ni/Ni interface showed a pre‐existing passive layer and interfacial defects. The interface was more prone to attack than the Ni base. Pitting corrosion along the interface boundary occurs via three main processes—initiation, growth, and pit coalescence—with a corresponding reduction in the interfacial adhesion strength and ultimately the structural integrity. The combination of substrate modification (degreasing and pickling) and heat posttreatment effectively avoids localized corrosion. We believe that the surface activation and thermally induced diffusion have worked.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"15 1","pages":"961 - 970"},"PeriodicalIF":0.0,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74332939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fabrication and properties of the superhydrophobic ceria‐based composite coating on magnesium alloy","authors":"Jing Yuan, Rui Yuan, Pei Li, Duo-lu Mao, Tao Feng","doi":"10.1002/maco.202112359","DOIUrl":"https://doi.org/10.1002/maco.202112359","url":null,"abstract":"A superhydrophobic ceria‐based composite coating is developed to improve anticorrosion properties of AZ61 magnesium alloy, fabricating via chemical conversion method followed by hydrothermal treatment. The cerium conversion coating has a block structure with microcracks. After the hydrothermal treatment, a dense CeO2 layer, porous CeO2 nanorods, and stearic absorbing layers are grown stepwise on the conversion coating. And the composite coating is hydrophobic or even superhydrophobic and has almost no microcracks. As the hydrothermal reaction time increases, the water contact angle of the composite coating first increases and then decreases, and it reaches the maximum value of 152° after hydrothermal treatment for 4 h. Both the dense CeO2 layer and the superhydrophobic stearic absorbing layer can effectively prevent the electrolyte from contacting the substrate; the corrosion current density of the superhydrophobic composite coating is lower than that of the hydrophilic composite coating and the cerium conversion coating, and has the best corrosion resistance.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"21 1","pages":"1305 - 1314"},"PeriodicalIF":0.0,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74128352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electrochemical corrosion behavior and microstructural characteristics of electron beam welded UNS S32205 duplex stainless steel","authors":"J. Singh, A. S. Shahi","doi":"10.1002/maco.202012201","DOIUrl":"https://doi.org/10.1002/maco.202012201","url":null,"abstract":"Different electrochemical techniques were used to study the corrosion behavior of UNS S32205 duplex stainless steel (DSS) welded autogenously using a single‐pass by electron beam welding process, supplemented by microstructural characterization. Furthermore, a comparative study was also performed between multipass gas tungsten arc (GTA)‐welded and EB‐welded DSS for their microstructure and corrosion behavior. The differences in weld thermal cycle and chemical composition influenced the fusion zone microstructure of both the welds and eventually their corrosion properties. The general corrosion resistance of the EB weld was lower than the base metal and higher than the GTA weld despite its weld zone being characterized by a relatively unbalanced phase ratio (α/γ) in comparison to the GTA weld. However, the EB weld showed relatively higher susceptibility to pitting corrosion than the base metal and GTA weld due to its poor repassivation characteristics and poor resistance to pit growth.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"195 1","pages":"1350 - 1369"},"PeriodicalIF":0.0,"publicationDate":"2021-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82425002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dejia Liu, Jiaxin Yu, Yafeng Zhang, Yong-gan Zhang, M. Shen
{"title":"Corrosion behavior of friction stir‐welded AZ31 Mg alloy after plastic deformation","authors":"Dejia Liu, Jiaxin Yu, Yafeng Zhang, Yong-gan Zhang, M. Shen","doi":"10.1002/maco.202112311","DOIUrl":"https://doi.org/10.1002/maco.202112311","url":null,"abstract":"Postweld plastic deformation was reported to be able to largely enhance the mechanical properties of friction stir‐welded (FSW) Mg alloys by changing microstructures in the regions with a soft‐oriented texture. However, few studies have concentrated on the effects of postweld plastic deformations on the corrosion behavior of FSW Mg alloys, which has an impact on their application. In the present study, electrochemical measurements, hydrogen evolution, and mass loss tests were used to study the influences of postweld compression along the transverse direction and subsequent annealing on the corrosion rate of FSW AZ31 Mg alloys. It was found that owing to the grain refinement in the weld zones, an improvement in the corrosion resistance and hardness was observed in the FSW AZ31 sample compared to the base metal (BM) sample. Postweld compression was very harmful to the corrosion resistance of the FSW AZ31 alloys. On the basis of the mass loss results, the corrosion rate of the compressed FSW sample was ~17.62 mm/year, which was ~8.99 times that of the FSW sample (~1.96 mm/year). Subsequent annealing could slightly reduce the corrosion rate of the compressed FSW AZ31 plates, whereas the corrosion rate of the FSW‐C‐T sample (~13.63 mm/year) was much worse than that of the BM sample (~4.73 mm/year).","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"4 1","pages":"1294 - 1304"},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85204320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Pillai, S. Pearson, M. Gussev, T. Watkins, B. Pint
{"title":"Quantifying adherence of oxide scales on steels exposed to high temperature and pressure steam","authors":"R. Pillai, S. Pearson, M. Gussev, T. Watkins, B. Pint","doi":"10.1002/maco.202012260","DOIUrl":"https://doi.org/10.1002/maco.202012260","url":null,"abstract":"Oxide scale exfoliation is a major concern in fossil fuel power generation because it can cause tube blockages and erode valves and steam turbine components downstream. There is still considerable scientific and commercial interest to improve the mechanistic understanding of oxide failures by developing models to predict exfoliation and the extent of tube blockage as a function of operating conditions and component geometries. Tensile testing inside a scanning electron microscope was conducted on ferritic–martensitic and austenitic steel specimens with the steam side (Fe,Cr)‐rich oxides grown after exposures for up to 1000 h in steam with ~100 ppb O2 at 276 bar and 550°C. Multiple oxide layer cracks and delamination events were observed and analyzed in detail during the tests. Results from the testing agreed well with earlier observations that had identified the failure location at the outer–inner oxide layer for all tested materials. Calculated adhesion energies identified the outer–inner oxide interface of alloy 347HFG as the weakest interface.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"1 1","pages":"1315 - 1327"},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75741454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Neupane, S. Hastuty, Neelima Yadav, Nilima Singh, D. Gupta, B. Yadav, Sanjay Singh, N. Karki, Anju Kumari Das, Vivek Subedi, Krishna Badan Nakarmi, A. Yadav
{"title":"Effects of NH4\u0000+, Na+, and Mg2+ ions on the corrosion behavior of galvanized steel in wet–dry cyclic conditions","authors":"S. Neupane, S. Hastuty, Neelima Yadav, Nilima Singh, D. Gupta, B. Yadav, Sanjay Singh, N. Karki, Anju Kumari Das, Vivek Subedi, Krishna Badan Nakarmi, A. Yadav","doi":"10.1002/maco.202112360","DOIUrl":"https://doi.org/10.1002/maco.202112360","url":null,"abstract":"The effect of cations on the corrosion of galvanized steel (GS) is scarcely reported. In this study, a wet–dry cyclic test was conducted to study NH4 +, Na+, and Mg2+ cation effect on the corrosion behavior of GS available in Nepal. Fourteen wet–dry cycles (18 h wet and 6 h dry) were performed by exposing samples at 298 K with a relative humidity of 90% in a wet cycle and 50% in a dry cycle for 14 days. The cations strongly affect the corrosion rate of the GS sample estimated by weight loss and potentiodynamic polarization. The potentiodynamic polarization curves showed the inhibition of cathodic and anodic reactions by Mg2+ ion, while the NH4 + ion only changed the cathodic reaction. Mg2+ ion was found to shift the corrosion potential to noble values compared with NH4 + and Na+ ions. A compact and thin corrosion products layer was developed in Mg2+ salt solution in contrast to a thick and porous corrosion products layer in NH4 + and Na+ salt solutions. Red rust due to corrosion of underlying steel appeared in the presence of NH4 + and Na+ salt solutions. Finally, the weight loss data revealed that the corrosivity of cations for GS decreased in the order Na+ > NH4 + > Mg2+.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"149 1","pages":"1388 - 1395"},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75522137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}