The corrosion behavior of a galvanic coupling consisting of a 7075‐T6‐aluminum alloy and a low‐carbon low‐manganese microalloyed dual‐phase steel was studied in a 3% NaCl aqueous solution at room temperature. Corrosion behavior of the individual materials was assessed from potentiodynamic polarization and electrochemical impedance spectroscopy measurements conducted on the individual couple components. The corrosion rate of the individual samples was found to be seven times larger on the microalloyed steel than on the aluminum alloy. From a comparison of corrosion current densities, the galvanic couple was found to sustain a nonsignificant galvanic effect—the latter in contrast to what may be determined considering differences in their respective corrosion potentials. According to the applied mixed‐potential theory and the zero‐resistance‐ammeter measurements performed directly on the galvanic couple, the aluminum‐alloy acted as the anodic member of the galvanic couple. Such behavior was justified by kinetic parameters rather than thermodynamic ones, considering the favorable rate of the oxygen reduction reaction on the microalloyed steel surface.
{"title":"Assessment of the galvanic corrosion of bi‐metallic couple 7075‐T6‐aluminum alloy/microalloyed dual‐phase steel","authors":"Vianey Torres, R. Mayén‐Mondragón, Juan Genesca","doi":"10.1002/maco.202112934","DOIUrl":"https://doi.org/10.1002/maco.202112934","url":null,"abstract":"The corrosion behavior of a galvanic coupling consisting of a 7075‐T6‐aluminum alloy and a low‐carbon low‐manganese microalloyed dual‐phase steel was studied in a 3% NaCl aqueous solution at room temperature. Corrosion behavior of the individual materials was assessed from potentiodynamic polarization and electrochemical impedance spectroscopy measurements conducted on the individual couple components. The corrosion rate of the individual samples was found to be seven times larger on the microalloyed steel than on the aluminum alloy. From a comparison of corrosion current densities, the galvanic couple was found to sustain a nonsignificant galvanic effect—the latter in contrast to what may be determined considering differences in their respective corrosion potentials. According to the applied mixed‐potential theory and the zero‐resistance‐ammeter measurements performed directly on the galvanic couple, the aluminum‐alloy acted as the anodic member of the galvanic couple. Such behavior was justified by kinetic parameters rather than thermodynamic ones, considering the favorable rate of the oxygen reduction reaction on the microalloyed steel surface.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"6 1","pages":"940 - 949"},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82123383","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}
Jie-zhen Hu, Huan Huang, P. Deng, Gui Wang, Mingfa Wu, Wenjuan Liu
In this study, the galvanic corrosion behavior of the side surface of titanium‐clad steel plate (TCSP) and below the defects, which penetrate through the titanium layer of TCSP, have been focused on. Electrochemical corrosion tests and infinite focus three‐dimensional measurement results revealed that galvanic corrosion on the side of TCSP will lead to widespread pitting of the steel, and the distribution positions of pits in splash, tidal, and submerged zones are different. Severe corrosion occurs below the defects in the titanium layer of TCSP, and the larger the defect, the deeper the corrosion depth, but TCSP with smaller defects have larger corrosion width on the Ti‐Stl line (the joint between the titanium and steel). This shows that the size of the defect will influence the density of corrosion products and the effect of TCSP defect internal corrosion on titanium layer peeling is extremely limited.
{"title":"Galvanic corrosion behavior of titanium‐clad steel plate in the marine environment","authors":"Jie-zhen Hu, Huan Huang, P. Deng, Gui Wang, Mingfa Wu, Wenjuan Liu","doi":"10.1002/maco.202113019","DOIUrl":"https://doi.org/10.1002/maco.202113019","url":null,"abstract":"In this study, the galvanic corrosion behavior of the side surface of titanium‐clad steel plate (TCSP) and below the defects, which penetrate through the titanium layer of TCSP, have been focused on. Electrochemical corrosion tests and infinite focus three‐dimensional measurement results revealed that galvanic corrosion on the side of TCSP will lead to widespread pitting of the steel, and the distribution positions of pits in splash, tidal, and submerged zones are different. Severe corrosion occurs below the defects in the titanium layer of TCSP, and the larger the defect, the deeper the corrosion depth, but TCSP with smaller defects have larger corrosion width on the Ti‐Stl line (the joint between the titanium and steel). This shows that the size of the defect will influence the density of corrosion products and the effect of TCSP defect internal corrosion on titanium layer peeling is extremely limited.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"32 1","pages":"887 - 896"},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88488379","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}
Dunja Marunkić, Jovana Pejić, B. Jegdić, A. Marinković, Bojana M. Radojković
The corrosion behaviour of high‐strength AA7075 aluminium alloy in NaCl solution, without and in the presence of environmentally friendly corrosion inhibitors (Ce‐chloride and Ce‐citrate) in low concentrations (<0.5 mM), was analysed. The degree of precipitation of the solid solution of AA7075 alloy was determined by measuring the electrical conductivity, while the surface morphology and appearance of intermetallic compounds before and after corrosion testing were analysed by SEM/EDS method. The general corrosion resistance of the tested alloy in NaCl solution and the degree of the inhibitory effect of the corrosion inhibitors were determined on the basis of electrochemical impedance spectroscopy and polarization measurements, while resistance to pit formation on the bases of Epit. AA7075 alloy showed high resistance to general corrosion in the presence of both tested inhibitors, while resistance to pit formation was significantly higher in the presence of Ce‐citrate (concentration 0.5 mM). Also, Ce‐citrate present in NaCl solution at lower concentrations provides satisfactory resistance of AA7075 alloy to general and pitting corrosion. A mechanism of protective action of Ce‐citrate inhibitor has been proposed.
{"title":"Cerium citrate as ecologically friendly corrosion inhibitor for AA7075 alloy","authors":"Dunja Marunkić, Jovana Pejić, B. Jegdić, A. Marinković, Bojana M. Radojković","doi":"10.1002/maco.202112900","DOIUrl":"https://doi.org/10.1002/maco.202112900","url":null,"abstract":"The corrosion behaviour of high‐strength AA7075 aluminium alloy in NaCl solution, without and in the presence of environmentally friendly corrosion inhibitors (Ce‐chloride and Ce‐citrate) in low concentrations (<0.5 mM), was analysed. The degree of precipitation of the solid solution of AA7075 alloy was determined by measuring the electrical conductivity, while the surface morphology and appearance of intermetallic compounds before and after corrosion testing were analysed by SEM/EDS method. The general corrosion resistance of the tested alloy in NaCl solution and the degree of the inhibitory effect of the corrosion inhibitors were determined on the basis of electrochemical impedance spectroscopy and polarization measurements, while resistance to pit formation on the bases of Epit. AA7075 alloy showed high resistance to general corrosion in the presence of both tested inhibitors, while resistance to pit formation was significantly higher in the presence of Ce‐citrate (concentration 0.5 mM). Also, Ce‐citrate present in NaCl solution at lower concentrations provides satisfactory resistance of AA7075 alloy to general and pitting corrosion. A mechanism of protective action of Ce‐citrate inhibitor has been proposed.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"82 1","pages":"950 - 960"},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73894774","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}
B. Shi, Xixun Shen, Gaofei Liang, Yanshaozuo Zhu, Qunjie Xu
The acid‐resistant steel represented by 09CrCuSb (ND) steel that is widely used in flue gas treatment systems is easily prone to mixed‐acid dew point corrosion in the low‐temperature flue gas environment. To improve the corrosion resistance of ND steel in a low‐temperature dew point corrosion environment, here, a chromium–myristate hybrid (CMH) superhydrophobic coating is proposed as a low‐temperature dew point corrosion protective coating for the ND steel substrate. This superhydrophobic coating is deposited on the ND steel substrate (preplated dark nickel as a transition layer) by one‐step direct current electrodeposition. The electrochemical analysis from potentiodynamic polarization and electrochemical impedance spectroscopy and the immersion test show that the CMH superhydrophobic coating can significantly improve the corrosion resistance of the ND substrate. Therefore, the present study provides a feasible strategy for preventing the mixed‐acid dew point corrosion of ND steel in the low‐temperature zone.
{"title":"The superhydrophobic coating with low‐temperature dew point corrosion resistance on an acid‐resistant steel substrate prepared by the electrodeposition method","authors":"B. Shi, Xixun Shen, Gaofei Liang, Yanshaozuo Zhu, Qunjie Xu","doi":"10.1002/maco.202112832","DOIUrl":"https://doi.org/10.1002/maco.202112832","url":null,"abstract":"The acid‐resistant steel represented by 09CrCuSb (ND) steel that is widely used in flue gas treatment systems is easily prone to mixed‐acid dew point corrosion in the low‐temperature flue gas environment. To improve the corrosion resistance of ND steel in a low‐temperature dew point corrosion environment, here, a chromium–myristate hybrid (CMH) superhydrophobic coating is proposed as a low‐temperature dew point corrosion protective coating for the ND steel substrate. This superhydrophobic coating is deposited on the ND steel substrate (preplated dark nickel as a transition layer) by one‐step direct current electrodeposition. The electrochemical analysis from potentiodynamic polarization and electrochemical impedance spectroscopy and the immersion test show that the CMH superhydrophobic coating can significantly improve the corrosion resistance of the ND substrate. Therefore, the present study provides a feasible strategy for preventing the mixed‐acid dew point corrosion of ND steel in the low‐temperature zone.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"36 1","pages":"903 - 917"},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85112183","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}
Y. V. Harinath, P. Chandramohan, B. Anandkumar, T. Mohan, S. Rangarajan, S. Albert
Many studies have revealed that Hastelloy‐N is the most suitable material for molten FLiNaK salt application. However, due to the nonavailability and high cost of Hastelloy‐N, Incoloy‐800HT is being considered as an alternate material. Corrosion studies were carried out on Incoloy‐800HT in vacuum‐dried molten FLiNaK salt at 650°C and 750°C for 100, 250, 500 and 1000 h. The exposed specimens were examined for weight loss and subjected to surface analysis using techniques like metallography, confocal laser scanning microscopy, X‐ray diffraction and laser Raman spectroscopy. The results revealed that the weight loss and depth of attack are less in specimens exposed to 650°C than those exposed to 750°C, and there is no evidence of any localised attack at both the temperatures. Chemical analysis of the used salt showed higher Cr and Fe contents than that in fresh salt, indicating dealloying of elements like Cr and Fe from Incoloy‐800HT specimens during exposure to molten FLiNaK salt. Oxides rich in Fe and Cr with spinel‐type crystal structures were identified on the exposed surfaces. From the results, it could be concluded that though there was considerable corrosion of Incoloy‐800HT, the material may be used in static molten FLiNaK salt systems with limited design life restricted to a temperature of 650°C by giving appropriate corrosion allowance.
{"title":"Degradation of Incoloy‐800HT in molten FLiNaK salt at high temperatures","authors":"Y. V. Harinath, P. Chandramohan, B. Anandkumar, T. Mohan, S. Rangarajan, S. Albert","doi":"10.1002/maco.202112758","DOIUrl":"https://doi.org/10.1002/maco.202112758","url":null,"abstract":"Many studies have revealed that Hastelloy‐N is the most suitable material for molten FLiNaK salt application. However, due to the nonavailability and high cost of Hastelloy‐N, Incoloy‐800HT is being considered as an alternate material. Corrosion studies were carried out on Incoloy‐800HT in vacuum‐dried molten FLiNaK salt at 650°C and 750°C for 100, 250, 500 and 1000 h. The exposed specimens were examined for weight loss and subjected to surface analysis using techniques like metallography, confocal laser scanning microscopy, X‐ray diffraction and laser Raman spectroscopy. The results revealed that the weight loss and depth of attack are less in specimens exposed to 650°C than those exposed to 750°C, and there is no evidence of any localised attack at both the temperatures. Chemical analysis of the used salt showed higher Cr and Fe contents than that in fresh salt, indicating dealloying of elements like Cr and Fe from Incoloy‐800HT specimens during exposure to molten FLiNaK salt. Oxides rich in Fe and Cr with spinel‐type crystal structures were identified on the exposed surfaces. From the results, it could be concluded that though there was considerable corrosion of Incoloy‐800HT, the material may be used in static molten FLiNaK salt systems with limited design life restricted to a temperature of 650°C by giving appropriate corrosion allowance.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"443 1","pages":"771 - 783"},"PeriodicalIF":0.0,"publicationDate":"2022-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86856868","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}
The addition of tara and quebracho colorado tannins remarkably reduces the corrosion rate of aluminum in near‐neutral and naturally aerated NaCl solutions. The experimental results (potentiodynamic polarization curves, corrosion potential measurements, scanning electron microscopy–energy‐dispersive X‐ray spectroscopy [SEM‐EDS] analysis on exposed surfaces) show that both tannins behave as a mixed‐type corrosion inhibitor of aluminum. In the absence of tannins, the SEM‐EDS analysis of the exposed samples demonstrates the accumulation of corrosion products and the existence of chlorinated compounds adsorbed on the metal surface. In the samples immersed in both tannins solutions, a more homogenous and compact layer is formed over the aluminum surface. Furthermore, in these layers chlorine was not found, revealing a high blocking capacity of the chloride adsorption when the tannins are present. Taking into account these findings, an inhibitory mechanism of aluminum corrosion is proposed. This mechanism is interphase inhibition, which involves the adsorption and incorporation of tannin molecules during the corrosion products passive layer formation, resulting in a protective three‐dimensional structure that retards both anodic and cathodic reactions.
{"title":"Tannins as interphase corrosion inhibitors for aluminum in near‐neutral chloride solutions","authors":"C. Byrne, Oriana D'Alessandro, C. Deyá","doi":"10.1002/maco.202112765","DOIUrl":"https://doi.org/10.1002/maco.202112765","url":null,"abstract":"The addition of tara and quebracho colorado tannins remarkably reduces the corrosion rate of aluminum in near‐neutral and naturally aerated NaCl solutions. The experimental results (potentiodynamic polarization curves, corrosion potential measurements, scanning electron microscopy–energy‐dispersive X‐ray spectroscopy [SEM‐EDS] analysis on exposed surfaces) show that both tannins behave as a mixed‐type corrosion inhibitor of aluminum. In the absence of tannins, the SEM‐EDS analysis of the exposed samples demonstrates the accumulation of corrosion products and the existence of chlorinated compounds adsorbed on the metal surface. In the samples immersed in both tannins solutions, a more homogenous and compact layer is formed over the aluminum surface. Furthermore, in these layers chlorine was not found, revealing a high blocking capacity of the chloride adsorption when the tannins are present. Taking into account these findings, an inhibitory mechanism of aluminum corrosion is proposed. This mechanism is interphase inhibition, which involves the adsorption and incorporation of tannin molecules during the corrosion products passive layer formation, resulting in a protective three‐dimensional structure that retards both anodic and cathodic reactions.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"65 1","pages":"798 - 810"},"PeriodicalIF":0.0,"publicationDate":"2022-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89834856","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}
E‐coated galvanized steel sheets are widespread parts of the automotive industry. Hence, the undermining of the organic coating due to defects is a crucial issue. The delamination of an e‐coating is simulated for different cyclic climate conditions using the finite element method to predict the corrosion behavior over several weeks. A semiempirical mixed potential theory model is developed incorporating the time‐of‐wetness, the temperature, and the effect of corrosion products. Furthermore, the spatial orientation of the sheets is considered in the simulation. The trends of experimental delamination widths of corrosion tests are well described by the simulation.
{"title":"Enhanced predictive corrosion modeling of crevice evolution at e‐coat defects under cyclic climate conditions","authors":"Benjamin Wagner, Andreas Mittelbach, P. Geiss","doi":"10.1002/maco.202112930","DOIUrl":"https://doi.org/10.1002/maco.202112930","url":null,"abstract":"E‐coated galvanized steel sheets are widespread parts of the automotive industry. Hence, the undermining of the organic coating due to defects is a crucial issue. The delamination of an e‐coating is simulated for different cyclic climate conditions using the finite element method to predict the corrosion behavior over several weeks. A semiempirical mixed potential theory model is developed incorporating the time‐of‐wetness, the temperature, and the effect of corrosion products. Furthermore, the spatial orientation of the sheets is considered in the simulation. The trends of experimental delamination widths of corrosion tests are well described by the simulation.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"16 1","pages":"703 - 709"},"PeriodicalIF":0.0,"publicationDate":"2022-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87839227","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}
Qing Liao, Bingsheng Li, F. Ge, Renda Wang, Hongpeng Zhang, V. Kršjak, Yanbin Sheng
Ferritic/martensitic steel was chosen as a primary candidate structural material for China Initiative Accelerator Driven System (CiADS) which started in 2015. A new kind of tempered martensitic steel, Steel of Institute of Modern Physics (SIMP), was designed to meet the requirements of the special operating environment. Structural materials suffer from liquid Pb‐Bi corrosion and liquid metal wetting at 450°C. Liquid metal wetting can seriously affect the mechanical properties of structural materials due to the decrease in surface energy and transition from martensitic laths to ferritic grains. Creep‐to‐rupture of SIMP steel was explored in stagnant liquid Pb‐Bi eutectic at 450°C. The possible reasons for creep‐to‐rupture are discussed. The results of the present study provide a new insight into challenges related to the application of SIMP steel in CiADS.
{"title":"Investigation into creep‐to‐rupture of SIMP steel in stagnant LBE at 300–450°C","authors":"Qing Liao, Bingsheng Li, F. Ge, Renda Wang, Hongpeng Zhang, V. Kršjak, Yanbin Sheng","doi":"10.1002/maco.202112887","DOIUrl":"https://doi.org/10.1002/maco.202112887","url":null,"abstract":"Ferritic/martensitic steel was chosen as a primary candidate structural material for China Initiative Accelerator Driven System (CiADS) which started in 2015. A new kind of tempered martensitic steel, Steel of Institute of Modern Physics (SIMP), was designed to meet the requirements of the special operating environment. Structural materials suffer from liquid Pb‐Bi corrosion and liquid metal wetting at 450°C. Liquid metal wetting can seriously affect the mechanical properties of structural materials due to the decrease in surface energy and transition from martensitic laths to ferritic grains. Creep‐to‐rupture of SIMP steel was explored in stagnant liquid Pb‐Bi eutectic at 450°C. The possible reasons for creep‐to‐rupture are discussed. The results of the present study provide a new insight into challenges related to the application of SIMP steel in CiADS.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"52 1","pages":"784 - 797"},"PeriodicalIF":0.0,"publicationDate":"2022-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78210966","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}
Beibei Zhang, G. Wang, Shenghua Ma, Hui Wang, J. Bai
Biomass, as a green and renewable energy source, can be procured from a broad range of sources and is low in cost. The full exploitation of biomass could reduce the dependence on and consumption of fossil fuels, and is conducive to the protection of the environment. The prevention of corrosion of metals is an issue considered problematic in many fields, including in industrial production among others. Many anticorrosion materials are expensive and are noxious to the environment. This is an important issue that anticorrosion workers cannot ignore. This study proposes the use of biochar epoxy to boost the barrier properties of the coating, which is both economical and eco‐friendly. The incorporation of biochar can reduce the porosity of the coating and complicate the path of the corrosive media towards the steel substrate. Additionally, it can also reinforce the anticorrosion performance of the coatings. First, this article introduces the effect of biochars with different ultrasonic durations on the anticorrosion performance of anticorrosion coatings. After finding the biochar with the optimal ultrasonic duration, the effects of biochar on the anticorrosion performance of the coatings at different temperatures are assessed and the changes in its anticorrosion performance following soaking are discussed. The discussion concludes that applying biochar to anticorrosion coatings provides a feasible type of coating for anticorrosion work.
{"title":"Enhancement of barrier and corrosion protection performance of epoxy coatings through adding eco‐friendly lamellar biochar","authors":"Beibei Zhang, G. Wang, Shenghua Ma, Hui Wang, J. Bai","doi":"10.1002/maco.202112697","DOIUrl":"https://doi.org/10.1002/maco.202112697","url":null,"abstract":"Biomass, as a green and renewable energy source, can be procured from a broad range of sources and is low in cost. The full exploitation of biomass could reduce the dependence on and consumption of fossil fuels, and is conducive to the protection of the environment. The prevention of corrosion of metals is an issue considered problematic in many fields, including in industrial production among others. Many anticorrosion materials are expensive and are noxious to the environment. This is an important issue that anticorrosion workers cannot ignore. This study proposes the use of biochar epoxy to boost the barrier properties of the coating, which is both economical and eco‐friendly. The incorporation of biochar can reduce the porosity of the coating and complicate the path of the corrosive media towards the steel substrate. Additionally, it can also reinforce the anticorrosion performance of the coatings. First, this article introduces the effect of biochars with different ultrasonic durations on the anticorrosion performance of anticorrosion coatings. After finding the biochar with the optimal ultrasonic duration, the effects of biochar on the anticorrosion performance of the coatings at different temperatures are assessed and the changes in its anticorrosion performance following soaking are discussed. The discussion concludes that applying biochar to anticorrosion coatings provides a feasible type of coating for anticorrosion work.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"46 1","pages":"720 - 732"},"PeriodicalIF":0.0,"publicationDate":"2022-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86766034","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}
Xuzheng Qian, Waner Zhao, W. Zhan, Tianyue Zhang, Jingjing Pan, Yiting Liu
A novel type of Co–Ti–Mo conversion coating (CoTiMoCC) was prepared on LY12 aluminum alloy, furthermore the optimal formula and the effect of conversion time (CTI) were studied in detail. The micromorphology and phase compositions were systematically investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy, and the corrosion resistance was determined by dropping test, electrochemical tests, and immersion test. Results reveal that the best formula of CoTiMoCC is Co2SO4: 2.0 g/L, H2TiF6: 1.5 ml/L, and Na2MoO4: 1.0 g/L and the corresponding optimal CTI is 16 min. Significantly, the micromorphology of CoTiMoCC under the best conversion condition is relatively smooth, continuous, and dense, and the major elements on the surface are Co, Ti, Mo, Al, O, and F. The phase compositions mainly consist of CoO, Co3O4, MoO3, Mo2O5, TiO2, and Al2O3, as well as a small quantity of AlF3·3H2O and Na3AlF6. Compared with the Al alloy matrix, CoTiMoCC acquires an order of magnitude lower Icorr and thus significantly reduces its corrosion rate, which is also confirmed by electrochemical impedance spectroscopy results. Further study of immersion test exhibits that the corrosion resistance of CoTiMoCC is approximately five times that of Al alloy matrix, and no obvious corrosion spots are generated on its surface.
{"title":"Formation and corrosion resistance of a novel Co–Ti–Mo composite chromium‐free chemical conversion coating on LY12 aluminum alloy","authors":"Xuzheng Qian, Waner Zhao, W. Zhan, Tianyue Zhang, Jingjing Pan, Yiting Liu","doi":"10.1002/maco.202112951","DOIUrl":"https://doi.org/10.1002/maco.202112951","url":null,"abstract":"A novel type of Co–Ti–Mo conversion coating (CoTiMoCC) was prepared on LY12 aluminum alloy, furthermore the optimal formula and the effect of conversion time (CTI) were studied in detail. The micromorphology and phase compositions were systematically investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy, and the corrosion resistance was determined by dropping test, electrochemical tests, and immersion test. Results reveal that the best formula of CoTiMoCC is Co2SO4: 2.0 g/L, H2TiF6: 1.5 ml/L, and Na2MoO4: 1.0 g/L and the corresponding optimal CTI is 16 min. Significantly, the micromorphology of CoTiMoCC under the best conversion condition is relatively smooth, continuous, and dense, and the major elements on the surface are Co, Ti, Mo, Al, O, and F. The phase compositions mainly consist of CoO, Co3O4, MoO3, Mo2O5, TiO2, and Al2O3, as well as a small quantity of AlF3·3H2O and Na3AlF6. Compared with the Al alloy matrix, CoTiMoCC acquires an order of magnitude lower Icorr and thus significantly reduces its corrosion rate, which is also confirmed by electrochemical impedance spectroscopy results. Further study of immersion test exhibits that the corrosion resistance of CoTiMoCC is approximately five times that of Al alloy matrix, and no obvious corrosion spots are generated on its surface.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"25 1","pages":"710 - 719"},"PeriodicalIF":0.0,"publicationDate":"2022-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76125394","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}
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