Monika Chlewicka, A. Dobkowska, R. Sitek, B. Adamczyk‐Cieślak, J. Mizera
The aim of this study is to produce Ti–AlN via selective laser melting. The results show that the microstructure of the produced alloy is not uniform. The X‐ray diffraction measurements show that the Ti–AlN composite is composed of a Ti matrix, AlN compounds, as well as (TiN)0.88, Al6Ti19, and Al1.1Ti0.9 intermetallics. The as‐printed Ti–AlN is also composed of dendrites of two typical titanium nitrides (TiN and Ti2N) and titanium aluminum nitride (Ti2AlN). Subsequent quenching and annealing slightly change the phase composition of the alloy and is the main reason for their different corrosion behaviors in acidic and chloride‐containing solutions. The results of this study show that the formation of Al‐rich ternary phases improved the corrosion resistance of the three‐dimensional‐printed Ti–AlN after quenching.
{"title":"Microstructure and corrosion resistance characteristics of Ti–AlN composite produced by selective laser melting","authors":"Monika Chlewicka, A. Dobkowska, R. Sitek, B. Adamczyk‐Cieślak, J. Mizera","doi":"10.1002/maco.202112703","DOIUrl":"https://doi.org/10.1002/maco.202112703","url":null,"abstract":"The aim of this study is to produce Ti–AlN via selective laser melting. The results show that the microstructure of the produced alloy is not uniform. The X‐ray diffraction measurements show that the Ti–AlN composite is composed of a Ti matrix, AlN compounds, as well as (TiN)0.88, Al6Ti19, and Al1.1Ti0.9 intermetallics. The as‐printed Ti–AlN is also composed of dendrites of two typical titanium nitrides (TiN and Ti2N) and titanium aluminum nitride (Ti2AlN). Subsequent quenching and annealing slightly change the phase composition of the alloy and is the main reason for their different corrosion behaviors in acidic and chloride‐containing solutions. The results of this study show that the formation of Al‐rich ternary phases improved the corrosion resistance of the three‐dimensional‐printed Ti–AlN after quenching.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"1 1","pages":"451 - 459"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88888859","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 corrosion inhibiting effect of the tannin from Acacia mearnsii bark on API 5CT K55 steel, used for casing in the oil and gas industry, was investigated in 1 M HCl medium with different tannin concentrations. Corrosion was monitored by electrochemical tests using potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). Complementary analyses of the corroded surfaces were performed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X‐ray diffraction (XRD). With the application of A. mearnsii tannin, the cathodic branch of the PP curves shifted to lower corrosion current density values. EIS analysis indicated that inhibitor molecules were adsorbed on the steel surface, which provided protection against corrosion. The SEM, AFM, and XRD data showed that in the presence of the inhibitor, a film and amorphous material were adsorbed on the steel surface, plausibly associated with the formation of tannates. The highest inhibition efficiency was obtained at an inhibitor concentration of 0.7 5 g L−1 (92% determined by PP and 98% by EIS), and a high degree of surface coverage was observed, compared with that obtained using the other concentrations of tannin.
在不同单宁浓度的1 M HCl介质中，研究了相思皮单宁对石油天然气套管用API 5CT K55钢的缓蚀作用。采用动电位极化(PP)和电化学阻抗谱(EIS)监测腐蚀情况。通过扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射仪(XRD)对腐蚀表面进行了补充分析。在单宁的作用下，PP曲线的阴极分支向较低的腐蚀电流密度值偏移。EIS分析表明，缓蚀剂分子被吸附在钢的表面，起到了抗腐蚀的作用。SEM, AFM和XRD数据表明，在抑制剂存在的情况下，钢表面吸附了一层薄膜和非晶物质，可能与单宁酸盐的形成有关。当抑制剂浓度为0.7 g L−1时，获得了最高的抑制效率(PP测定92%，EIS测定98%)，与使用其他浓度的单宁相比，观察到高的表面覆盖率。
{"title":"Inhibition of corrosion of API K55 steel by tannin from Acacia mearnsii bark in highly acidic medium","authors":"K. G. Bacca, N. Lopes, E. M. Costa","doi":"10.1002/maco.202112744","DOIUrl":"https://doi.org/10.1002/maco.202112744","url":null,"abstract":"The corrosion inhibiting effect of the tannin from Acacia mearnsii bark on API 5CT K55 steel, used for casing in the oil and gas industry, was investigated in 1 M HCl medium with different tannin concentrations. Corrosion was monitored by electrochemical tests using potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). Complementary analyses of the corroded surfaces were performed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X‐ray diffraction (XRD). With the application of A. mearnsii tannin, the cathodic branch of the PP curves shifted to lower corrosion current density values. EIS analysis indicated that inhibitor molecules were adsorbed on the steel surface, which provided protection against corrosion. The SEM, AFM, and XRD data showed that in the presence of the inhibitor, a film and amorphous material were adsorbed on the steel surface, plausibly associated with the formation of tannates. The highest inhibition efficiency was obtained at an inhibitor concentration of 0.7 5 g L−1 (92% determined by PP and 98% by EIS), and a high degree of surface coverage was observed, compared with that obtained using the other concentrations of tannin.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"88 3","pages":"613 - 622"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91452615","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}
Yucong Ma, M. Talha, Qi Wang, Qiancheng Zhao, Zhonghui Li, Yuanhua Lin
Chitosan (CTS) coatings have been studied as a biocompatible coating on biodegradable magnesium (Mg) alloys to improve the corrosion resistance and bioactivity for medical implants. However, the loose structure of the CTS coating cannot provide ideal long‐time corrosion resistance in the physiological environment. In this study, a nano‐SiO2/CTS composite coating was applied on an Mg alloy substrate using the sol–gel method. The surface characteristics of the samples were examined by Fourier‐transform infrared analysis, X‐ray diffraction, scanning electron microscopy‐energy‐dispersive spectrometry, and contact angle measurements. The particle size and suitable dispersion of the SiO2 nanoparticles inside the composite coating were confirmed by transmission electron microscopy. Further, the corrosion protection behavior of the coatings was examined in a simulated body fluid using potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electrochemical microscopy analyses. Atomic force microscopy was used to determine the surface morphologies of the samples after the polarization test. The surface characteristics, electrochemical measurements, and immersion test revealed that the SiO2 nanoparticles effectively filled the voids of the CTS coating and significantly improved the corrosion resistance. The optimal concentration of nano‐SiO2 is 1.0 g/L.
{"title":"Nano‐silica/chitosan composite coatings on biodegradable magnesium alloys for enhanced corrosion resistance in simulated body fluid","authors":"Yucong Ma, M. Talha, Qi Wang, Qiancheng Zhao, Zhonghui Li, Yuanhua Lin","doi":"10.1002/maco.202112701","DOIUrl":"https://doi.org/10.1002/maco.202112701","url":null,"abstract":"Chitosan (CTS) coatings have been studied as a biocompatible coating on biodegradable magnesium (Mg) alloys to improve the corrosion resistance and bioactivity for medical implants. However, the loose structure of the CTS coating cannot provide ideal long‐time corrosion resistance in the physiological environment. In this study, a nano‐SiO2/CTS composite coating was applied on an Mg alloy substrate using the sol–gel method. The surface characteristics of the samples were examined by Fourier‐transform infrared analysis, X‐ray diffraction, scanning electron microscopy‐energy‐dispersive spectrometry, and contact angle measurements. The particle size and suitable dispersion of the SiO2 nanoparticles inside the composite coating were confirmed by transmission electron microscopy. Further, the corrosion protection behavior of the coatings was examined in a simulated body fluid using potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electrochemical microscopy analyses. Atomic force microscopy was used to determine the surface morphologies of the samples after the polarization test. The surface characteristics, electrochemical measurements, and immersion test revealed that the SiO2 nanoparticles effectively filled the voids of the CTS coating and significantly improved the corrosion resistance. The optimal concentration of nano‐SiO2 is 1.0 g/L.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"2 1","pages":"436 - 450"},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86977733","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 relationship between the corrosion behavior of Mg–Gd–Y–Zn alloy and the content of rare earth elements was investigated. The results show that the Mg–4Gd–2Zn (VZ42) contains only α‐Mg matrix and W phase, while there are α‐Mg matrix, W phase and X phase in Mg–2Gd–2Y–2Zn (VWZ) and Mg–4Y–2Zn (WZ42). The corrosion rates measured by weight loss of VZ42, VWZ, and WZ42 are 8.17, 4.49, and 6.05 mm/year, respectively. Through the observation of microstructure, it is found that the corrosion first occurs around the W phase, which means that the micro galvanic effect caused by the W phase is more serious than that of the X phase. The more W phase, the greater the corrosion rate of the alloy. But continuously distributed layered X phase will form a barrier and protect α‐Mg from corrosion. It is found that different distribution of the second phase will also lead to different corrosion resistance.
{"title":"Study on the microstructure and corrosion behavior of Mg–(4 − x)Gd–xY–2Zn (x = 0, 2, 4 wt%) alloy","authors":"Yunhao Wang, Zili Liu, Xiqin Liu, Huanjian Xie, Yong Shi, Fang Liu, Jian Li","doi":"10.1002/maco.202112753","DOIUrl":"https://doi.org/10.1002/maco.202112753","url":null,"abstract":"The relationship between the corrosion behavior of Mg–Gd–Y–Zn alloy and the content of rare earth elements was investigated. The results show that the Mg–4Gd–2Zn (VZ42) contains only α‐Mg matrix and W phase, while there are α‐Mg matrix, W phase and X phase in Mg–2Gd–2Y–2Zn (VWZ) and Mg–4Y–2Zn (WZ42). The corrosion rates measured by weight loss of VZ42, VWZ, and WZ42 are 8.17, 4.49, and 6.05 mm/year, respectively. Through the observation of microstructure, it is found that the corrosion first occurs around the W phase, which means that the micro galvanic effect caused by the W phase is more serious than that of the X phase. The more W phase, the greater the corrosion rate of the alloy. But continuously distributed layered X phase will form a barrier and protect α‐Mg from corrosion. It is found that different distribution of the second phase will also lead to different corrosion resistance.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"63 1","pages":"602 - 612"},"PeriodicalIF":0.0,"publicationDate":"2021-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83997746","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}
Z. Golshani, Hossein Cheraghi Moezabad, Mahnaz Amiri, G. Sajadi, R. Naghizade, S. Hosseini
Natural extracts have been widely used to protect metal materials from corrosion. Mild steel (MS) corrosion inhibition in 0.5 M sulfuric acid was investigated in the absence and presence of Thyme leaf extracts as an economical corrosion inhibitor. The effects of various concentrations and different temperatures on inhibitor efficacy were investigated. Using electrochemical impedance spectroscopy and polarization curves, the corrosion resistance of the alloy was also estimated. The polarization technique indicated that the Thyme extract is a mixed‐type inhibitor for MS in 0.5 M H2SO4. The obtained results revealed an excellent inhibition efficiency of 98% at 200 ppm of Thyme concentration. The thermodynamic parameters calculated, the effects of temperature, and the adsorption mechanism were also investigated, that suggested formation of monolayer inhibitor molecules (i.e. the Langmuir adsorption isotherm) on the metal surface. The ∆Gadso value calculated from the Langmuir adsorption isotherm plots for inhibitor indicated that it was adsorbed on the alloy surface via a physisorption mechanism. Additional studies on plant extracts as corrosion inhibitors on metals are needed to produce solutions for industrial purposes.
天然提取物被广泛用于保护金属材料免受腐蚀。研究了百里香叶提取物在0.5 M硫酸中对低碳钢(MS)的缓蚀作用。考察了不同浓度和温度对缓蚀剂效果的影响。利用电化学阻抗谱和极化曲线对合金的耐蚀性进行了评价。极化技术表明百里香提取物在0.5 M H2SO4中为混合型质谱抑制剂。结果表明，在百里香浓度为200ppm时，百里香的抑菌率为98%。热力学参数的计算、温度的影响以及吸附机理的研究表明，金属表面形成了单层抑制剂分子(即Langmuir吸附等温线)。通过Langmuir吸附等温线图计算出缓蚀剂的∆Gadso值，表明缓蚀剂通过物理吸附机制吸附在合金表面。植物提取物作为金属的缓蚀剂需要进一步的研究，以生产工业用途的解决方案。
{"title":"Effect of Thyme extract as an ecofriendly inhibitor for corrosion of mild steel in acidic media","authors":"Z. Golshani, Hossein Cheraghi Moezabad, Mahnaz Amiri, G. Sajadi, R. Naghizade, S. Hosseini","doi":"10.1002/maco.202112769","DOIUrl":"https://doi.org/10.1002/maco.202112769","url":null,"abstract":"Natural extracts have been widely used to protect metal materials from corrosion. Mild steel (MS) corrosion inhibition in 0.5 M sulfuric acid was investigated in the absence and presence of Thyme leaf extracts as an economical corrosion inhibitor. The effects of various concentrations and different temperatures on inhibitor efficacy were investigated. Using electrochemical impedance spectroscopy and polarization curves, the corrosion resistance of the alloy was also estimated. The polarization technique indicated that the Thyme extract is a mixed‐type inhibitor for MS in 0.5 M H2SO4. The obtained results revealed an excellent inhibition efficiency of 98% at 200 ppm of Thyme concentration. The thermodynamic parameters calculated, the effects of temperature, and the adsorption mechanism were also investigated, that suggested formation of monolayer inhibitor molecules (i.e. the Langmuir adsorption isotherm) on the metal surface. The ∆Gadso value calculated from the Langmuir adsorption isotherm plots for inhibitor indicated that it was adsorbed on the alloy surface via a physisorption mechanism. Additional studies on plant extracts as corrosion inhibitors on metals are needed to produce solutions for industrial purposes.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"149 1","pages":"460 - 469"},"PeriodicalIF":0.0,"publicationDate":"2021-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75748045","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}
To enhance the mechanical properties and poor corrosion resistance of magnesium alloy in vitro, the as‐cast Mg–2Zn–0.5Zr–1.5Dy (mass%) magnesium alloy was subjected to two types of extrusion treatment, one is hot extrusion (denoted as ET alloy), the other is heat treatment followed by hot extrusion (denoted as HE alloy). The microstructure, mechanical properties, and corrosion behaviors of these extruded alloys are assessed. The results show that the HE alloy has superior mechanical properties and a slower corrosion rate than the ET alloy. The yield strength and elongation of the HE alloy reach 287 ± 10 MPa and 17.6 ± 0.5%, respectively, and its corrosion rate is only 0.59 ± 0.16 mm year−1. After hot extrusion, microscale and nanoscale second‐phase exist in the extruded alloys, and the nanoscale second‐phase can improve their mechanical properties by second‐phase strengthening. However, the presence of microscale second phase can cause galvanic corrosion and result in poor corrosion resistance. The HE alloy has good properties due to it containing more nanoscale second‐phase and fewer microscale second‐phase.
{"title":"Enhancement of mechanical properties and corrosion resistance of Mg–2Zn–0.5Zr–1.5Dy (mass%) alloy by a combination of heat treatment and hot extrusion","authors":"Huan Li, J. Wen, Ya Liu, Jun-guang He","doi":"10.1002/maco.202112755","DOIUrl":"https://doi.org/10.1002/maco.202112755","url":null,"abstract":"To enhance the mechanical properties and poor corrosion resistance of magnesium alloy in vitro, the as‐cast Mg–2Zn–0.5Zr–1.5Dy (mass%) magnesium alloy was subjected to two types of extrusion treatment, one is hot extrusion (denoted as ET alloy), the other is heat treatment followed by hot extrusion (denoted as HE alloy). The microstructure, mechanical properties, and corrosion behaviors of these extruded alloys are assessed. The results show that the HE alloy has superior mechanical properties and a slower corrosion rate than the ET alloy. The yield strength and elongation of the HE alloy reach 287 ± 10 MPa and 17.6 ± 0.5%, respectively, and its corrosion rate is only 0.59 ± 0.16 mm year−1. After hot extrusion, microscale and nanoscale second‐phase exist in the extruded alloys, and the nanoscale second‐phase can improve their mechanical properties by second‐phase strengthening. However, the presence of microscale second phase can cause galvanic corrosion and result in poor corrosion resistance. The HE alloy has good properties due to it containing more nanoscale second‐phase and fewer microscale second‐phase.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"19 1","pages":"587 - 601"},"PeriodicalIF":0.0,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86396303","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 equiatomic Co–Cr–Fe–Mn–Ni high‐entropy alloy (HEA) shows well hydrogen embrittlement resistance under monotonic tensile load. However, the fracture behavior under cyclic load is still unclear. In this study, combining with the fracture features analysis by electron back‐scattered diffraction and electron channeling contrast imaging techniques, the hydrogen‐assisted fatigue crack propagation behavior of equiatomic Co–Cr–Fe–Mn–Ni HEA under in situ electrochemical hydrogen charging was investigated. The results suggest that the hydrogen had significant accelerating effects on the fatigue crack growth rate of Co–Cr–Fe–Mn–Ni HEA. Intergranular cracking with the formation of dislocation cells was observed at low stress intensity range (ΔK) area, while transgranular cracking with deformation twins was observed at a high ΔK area. The formation of these deformation features was assisted by hydrogen‐assisted dislocation emission.
{"title":"Hydrogen‐assisted fatigue crack propagation behavior of equiatomic Co–Cr–Fe–Mn–Ni high‐entropy alloy","authors":"H. Xiao, Q. Zeng, Lin Xia, Z. Fu, Shaowei Zhu","doi":"10.1002/maco.202112866","DOIUrl":"https://doi.org/10.1002/maco.202112866","url":null,"abstract":"The equiatomic Co–Cr–Fe–Mn–Ni high‐entropy alloy (HEA) shows well hydrogen embrittlement resistance under monotonic tensile load. However, the fracture behavior under cyclic load is still unclear. In this study, combining with the fracture features analysis by electron back‐scattered diffraction and electron channeling contrast imaging techniques, the hydrogen‐assisted fatigue crack propagation behavior of equiatomic Co–Cr–Fe–Mn–Ni HEA under in situ electrochemical hydrogen charging was investigated. The results suggest that the hydrogen had significant accelerating effects on the fatigue crack growth rate of Co–Cr–Fe–Mn–Ni HEA. Intergranular cracking with the formation of dislocation cells was observed at low stress intensity range (ΔK) area, while transgranular cracking with deformation twins was observed at a high ΔK area. The formation of these deformation features was assisted by hydrogen‐assisted dislocation emission.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"16 12 1","pages":"550 - 557"},"PeriodicalIF":0.0,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86309705","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}
Considering the ionic liquids (ILs) were classified as green inhibitors herein three ecofriendly imidazolium‐based ILs were employed in corrosion inhibition, where weight loss evaluations along with electrochemical methods, including potentiodynamic polarization test, electrochemical impedance spectroscopy, and cyclic voltammetry measurements were exploited to elucidate corrosion prevention performance of the considered agents. The results derived from the polarization studies attested to the fact that these ILs could effectively act as mixed‐type corrosion inhibitors. Moreover, the progress of surface reactions due to the corrosion process was studied through field emission scanning electron microscopy and atomic force microscopy. Also, UV/Vis spectroscopy corroborated chemical interaction among metal surfaces and ILs. Findings clarified that the chemisorption of the ILs onto carbon steel surface conforms to Langmuir adsorption isotherm. Finally, it was found that all proposed ILs could play an effective role in corrosion preventing, for which, the efficiencies in the range of 82%–92% were achieved by electrochemical impedance analyses for investigated ILs at 75 ppm.
{"title":"Corrosion inhibiting performance of novel imidazolium‐based ionic liquids as an efficient and green corrosion constraint for carbon steel in neutral chloride solution","authors":"S. M. Shoja, M. Abdouss, A. M. Miran Beigi","doi":"10.1002/maco.202112751","DOIUrl":"https://doi.org/10.1002/maco.202112751","url":null,"abstract":"Considering the ionic liquids (ILs) were classified as green inhibitors herein three ecofriendly imidazolium‐based ILs were employed in corrosion inhibition, where weight loss evaluations along with electrochemical methods, including potentiodynamic polarization test, electrochemical impedance spectroscopy, and cyclic voltammetry measurements were exploited to elucidate corrosion prevention performance of the considered agents. The results derived from the polarization studies attested to the fact that these ILs could effectively act as mixed‐type corrosion inhibitors. Moreover, the progress of surface reactions due to the corrosion process was studied through field emission scanning electron microscopy and atomic force microscopy. Also, UV/Vis spectroscopy corroborated chemical interaction among metal surfaces and ILs. Findings clarified that the chemisorption of the ILs onto carbon steel surface conforms to Langmuir adsorption isotherm. Finally, it was found that all proposed ILs could play an effective role in corrosion preventing, for which, the efficiencies in the range of 82%–92% were achieved by electrochemical impedance analyses for investigated ILs at 75 ppm.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"27 1","pages":"623 - 640"},"PeriodicalIF":0.0,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78466941","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}
Q. Gao, H. Shang, Q. Ma, Huijie Zhang, Hailian Zhang, Huijun Li, Ziyun Liu
Co‐based superalloys with the advantages of high melting point, high‐temperature mechanical properties, and large resistance under hot corrosion environment are potential candidates for turbine engine components. The isothermal oxidation behavior of Co–Ni–Al‐based superalloy with the addition of Mo and Cr in dry air at 1073 and 1173 K was investigated. The results showed that similar three‐layer oxides structures were composed of Co‐containing oxides, complex oxides rich in Co and Al, and Al2O3 layer formed on both 2Mo and 2Cr Co–Ni–Al‐based superalloys, and Mo‐containing oxides also existed in the subsurface. The oxides in the outer layer transferred from Co3O4 to denser CoO with the increase in temperature. The γ'‐free zone formed under the Al2O3 layer due to the depletion of Al. Co–Ni–Al‐based superalloys need to conquer a large energy barrier at an earlier stage of oxidation and exhibit good oxidation resistance at 1073 K.
钴基高温合金具有高熔点、高温机械性能和在热腐蚀环境下抗腐蚀能力强等优点，是涡轮发动机部件的潜在候选材料。研究了Co-Ni-Al基高温合金在1073和1173 K干燥空气中Mo和Cr的等温氧化行为。结果表明:在2Mo和2Cr Co - ni - Al基高温合金表面均形成了相似的三层结构:含Co的氧化物、富含Co和Al的复合氧化物以及Al2O3层，并且在地下也存在含Mo的氧化物。随着温度的升高，外层的氧化物由Co3O4转变为较致密的CoO。由于Al的耗尽，在Al2O3层下形成了无γ区。Co-Ni-Al基高温合金需要在氧化早期克服较大的能垒，并在1073 K时表现出良好的抗氧化性。
{"title":"Isothermal oxidation behavior of W‐free Co–Ni–Al‐based superalloy at high temperature","authors":"Q. Gao, H. Shang, Q. Ma, Huijie Zhang, Hailian Zhang, Huijun Li, Ziyun Liu","doi":"10.1002/maco.202112789","DOIUrl":"https://doi.org/10.1002/maco.202112789","url":null,"abstract":"Co‐based superalloys with the advantages of high melting point, high‐temperature mechanical properties, and large resistance under hot corrosion environment are potential candidates for turbine engine components. The isothermal oxidation behavior of Co–Ni–Al‐based superalloy with the addition of Mo and Cr in dry air at 1073 and 1173 K was investigated. The results showed that similar three‐layer oxides structures were composed of Co‐containing oxides, complex oxides rich in Co and Al, and Al2O3 layer formed on both 2Mo and 2Cr Co–Ni–Al‐based superalloys, and Mo‐containing oxides also existed in the subsurface. The oxides in the outer layer transferred from Co3O4 to denser CoO with the increase in temperature. The γ'‐free zone formed under the Al2O3 layer due to the depletion of Al. Co–Ni–Al‐based superalloys need to conquer a large energy barrier at an earlier stage of oxidation and exhibit good oxidation resistance at 1073 K.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"17 1","pages":"513 - 525"},"PeriodicalIF":0.0,"publicationDate":"2021-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87761691","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}
Zhihao Liang, K. Jiang, Bai-ao Feng, Lin Li, Ting’an Zhang
The effect of the anode potential on the electrochemical performance and protective ability of the passive film formed on the brass alloy in the soil solution of the Zhouyuan site was investigated by electrochemical measurements, atomic force microscopy, and X‐ray photoelectron spectroscopy. The corrosion resistance of brass alloy in a corrosion soil environment decreases with the increase of applied anodic potential. X‐ray photoelectron spectroscopy results indicate that the passive film is mainly composed of metal oxide. Mott–Schottky results revealed that the passive films behave as p‐type semiconductors at passive potentials and the acceptor density is in the range of 1021 cm−3 and increased with an increase in the film‐forming potential.
{"title":"Effect of anodic potential on the characteristics of passive films grown on a brass alloy in a soil environment","authors":"Zhihao Liang, K. Jiang, Bai-ao Feng, Lin Li, Ting’an Zhang","doi":"10.1002/maco.202112795","DOIUrl":"https://doi.org/10.1002/maco.202112795","url":null,"abstract":"The effect of the anode potential on the electrochemical performance and protective ability of the passive film formed on the brass alloy in the soil solution of the Zhouyuan site was investigated by electrochemical measurements, atomic force microscopy, and X‐ray photoelectron spectroscopy. The corrosion resistance of brass alloy in a corrosion soil environment decreases with the increase of applied anodic potential. X‐ray photoelectron spectroscopy results indicate that the passive film is mainly composed of metal oxide. Mott–Schottky results revealed that the passive films behave as p‐type semiconductors at passive potentials and the acceptor density is in the range of 1021 cm−3 and increased with an increase in the film‐forming potential.","PeriodicalId":18223,"journal":{"name":"Materials and Corrosion","volume":"13 1","pages":"404 - 413"},"PeriodicalIF":0.0,"publicationDate":"2021-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81552730","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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