We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,an...We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,and 10.0 g/L of 2-mercaptobenzothiazole inhibitor.To examine this behavior,we conducted open-circuit potential(OCP),potentiodynamic polarization,and electrochemical impedance spectroscopy(EIS)tests.Energy dispersive spectroscopy and scanning electron microscopy were also used to analyze the corrosion products.The results of the OCP and potentiodynamic polarization tests revealed that 2-mercaptobenzothiazole reduces the speed of both the anodic and cathodic reactions.An assessment of the Gibbs free energy of the inhibitor(△G_(ads)^(■))indicated that its value was less than-20 kJ·mol^(-1)and greater than-40 k J·mol^(-1).Therefore,the adsorption of 2-mercaptobenzothiazole onto the surface of the API X60 pipeline steel occurs both physically and chemically,the latter of which is particularly intentional.In addition,as the△G_(ads)^(■)dsvalue was negative,we could conclude that the adsorption of 2-mercaptobenzothiazole onto the surface of the pipeline steel occurs spontaneously.The EIS results indicate that with the increase in the 2-mercaptobenzothiazole inhibitor concentration,the corrosion resistance of API X60 steel increases.An analysis of the corrosion products revealed that iron sulfide compounds form on the surface.In summary,the results showed that an increase in the inhibitor concentration results in a decrease in the corrosion rate and an increase in inhibitory efficiency.Additionally,we found that the 2-mercaptobenzothiazole adsorption process on the API X60 steel surfaces in an H2 S-containing environment follows the Langmuir adsorption isotherm and occurs spontaneously.展开更多
Effects of Ca2+ and Mg2+ on the CO2 corrosion behaviors of tube steel were studied in simulated oil-field environment.The influence of Ca2+and Mg2+ on the corrosion rate and morphologies of corrosion product layer was...Effects of Ca2+ and Mg2+ on the CO2 corrosion behaviors of tube steel were studied in simulated oil-field environment.The influence of Ca2+and Mg2+ on the corrosion rate and morphologies of corrosion product layer was determined by scanning electron microscope and measuring mass loss.Potentiodynamic polarization and impedance spectroscopy were used to investigate the change of electrochemical characteristic parameters of corrosion product layer and corrosion dynamic process.The results show that with Ca2+ and Mg2+ in electrolyte,the morphologies and microstructures of corrosion product layer changed obviously,thus affecting the corrosion process.展开更多
A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethano...A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethanolamine(DEA)aqueous solutions.The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature,activator concentration,CO2 loading and pH.The study consists of two major models:Vapor–liquid Equilibrium(VLE)model and electrochemical corrosion model.The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution.The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal.An increase in concentration of activator,increases the rate of corrosion of carbon steel in mixtures of activated DEA.展开更多
The corrosion behavior of high-strength steel used for flexible riser exposed to CO_(2-)saturated saline solution and CO_(2-) saturated vapor environments was studied through immersion experiment and electrochemical c...The corrosion behavior of high-strength steel used for flexible riser exposed to CO_(2-)saturated saline solution and CO_(2-) saturated vapor environments was studied through immersion experiment and electrochemical corrosion experiment. The corrosion behavior and mechanism of the tested steel were analyzed on the basis of corrosion kinetics, nature of corrosion products, corrosion product morphology, elemental distribution and polarization curves. The experimental results showed that the microstructure of the tested steel was bainitic microstructure. The corrosive activity of the tested steel exposed to CO_(2-) saturated vapor environment was significantly lower than that exposed to CO_(2-) saturated saline solution environment.On prolonging the exposure time, the corrosion rate gradually decreased, the corrosion heterogeneity increased, and the dimensions of FeCO_3 crystals gradually became small. At later stages of corrosion, the corrosion current density decreased significantly and the anodic Tafel slope increased, indicating that the corrosion process was strongly inhibited. The corrosion mechanism of low-alloy steel with bainitic microstructure was proposed based on experimental results.展开更多
The Co_(3)O_(4) decorated TiO_(2) nanotube arrays(NTAs)coatings are fabricated by the combination of anodization and impregnating methods.It is found that the introduction of Co_(3)O_(4) can reduce the diffraction int...The Co_(3)O_(4) decorated TiO_(2) nanotube arrays(NTAs)coatings are fabricated by the combination of anodization and impregnating methods.It is found that the introduction of Co_(3)O_(4) can reduce the diffraction intensity of(101)plane of the TiO_(2) and accelerate the separation of photogenerated electron/hole pairs.In addition,the open circuit potential(OCP)and the corrosion potential of 304 stainless steel(304SS)with or without Co_(3)O_(4) decorated TiO_(2) NTAs were measured under visible light,which indicated the 304SS coupled with Co_(3)O_(4) decorated TiO_(2) NTAs had better anticorrosion performance than that of the 304SS or the 304SS coupled with pure TiO_(2) NTAs.The enhancement of the cathodic protection performance of the Co_(3)O_(4) decorated TiO_(2) NTAs can be ascribed to the matched energy levels and strong interaction between Co_(3)O_(4) and TiO_(2) NTAs,and the improvement of light absorption.展开更多
A new intelligent amperometric type of electrochemical hydrogen probe to measure hydrogen atom permeation rate in the metals was devised and developed. Combined with MCS51 single slice computer system, specially progr...A new intelligent amperometric type of electrochemical hydrogen probe to measure hydrogen atom permeation rate in the metals was devised and developed. Combined with MCS51 single slice computer system, specially programmed software was designed for data sampling, logging, storing, processing, result judgment and data output controlling. The probe is portable and can be used in both lab and in site automatically.展开更多
文摘We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,and 10.0 g/L of 2-mercaptobenzothiazole inhibitor.To examine this behavior,we conducted open-circuit potential(OCP),potentiodynamic polarization,and electrochemical impedance spectroscopy(EIS)tests.Energy dispersive spectroscopy and scanning electron microscopy were also used to analyze the corrosion products.The results of the OCP and potentiodynamic polarization tests revealed that 2-mercaptobenzothiazole reduces the speed of both the anodic and cathodic reactions.An assessment of the Gibbs free energy of the inhibitor(△G_(ads)^(■))indicated that its value was less than-20 kJ·mol^(-1)and greater than-40 k J·mol^(-1).Therefore,the adsorption of 2-mercaptobenzothiazole onto the surface of the API X60 pipeline steel occurs both physically and chemically,the latter of which is particularly intentional.In addition,as the△G_(ads)^(■)dsvalue was negative,we could conclude that the adsorption of 2-mercaptobenzothiazole onto the surface of the pipeline steel occurs spontaneously.The EIS results indicate that with the increase in the 2-mercaptobenzothiazole inhibitor concentration,the corrosion resistance of API X60 steel increases.An analysis of the corrosion products revealed that iron sulfide compounds form on the surface.In summary,the results showed that an increase in the inhibitor concentration results in a decrease in the corrosion rate and an increase in inhibitory efficiency.Additionally,we found that the 2-mercaptobenzothiazole adsorption process on the API X60 steel surfaces in an H2 S-containing environment follows the Langmuir adsorption isotherm and occurs spontaneously.
基金Item Sponsored by National Natural Science Foundation of China(50231020)National Key Fundamental Research and Development Project of China(G1999065004)
文摘Effects of Ca2+ and Mg2+ on the CO2 corrosion behaviors of tube steel were studied in simulated oil-field environment.The influence of Ca2+and Mg2+ on the corrosion rate and morphologies of corrosion product layer was determined by scanning electron microscope and measuring mass loss.Potentiodynamic polarization and impedance spectroscopy were used to investigate the change of electrochemical characteristic parameters of corrosion product layer and corrosion dynamic process.The results show that with Ca2+ and Mg2+ in electrolyte,the morphologies and microstructures of corrosion product layer changed obviously,thus affecting the corrosion process.
基金the financial support provided by the Ministry of Higher Education&Scientific Research of Iraq。
文摘A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethanolamine(DEA)aqueous solutions.The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature,activator concentration,CO2 loading and pH.The study consists of two major models:Vapor–liquid Equilibrium(VLE)model and electrochemical corrosion model.The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution.The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal.An increase in concentration of activator,increases the rate of corrosion of carbon steel in mixtures of activated DEA.
基金financial support from the National High Technology Research and Development Program of China (Grant No. 2015AA03A501)Doctoral Scientific Research Foundation of Jiangsu University of Science and Technology (1062931702)
文摘The corrosion behavior of high-strength steel used for flexible riser exposed to CO_(2-)saturated saline solution and CO_(2-) saturated vapor environments was studied through immersion experiment and electrochemical corrosion experiment. The corrosion behavior and mechanism of the tested steel were analyzed on the basis of corrosion kinetics, nature of corrosion products, corrosion product morphology, elemental distribution and polarization curves. The experimental results showed that the microstructure of the tested steel was bainitic microstructure. The corrosive activity of the tested steel exposed to CO_(2-) saturated vapor environment was significantly lower than that exposed to CO_(2-) saturated saline solution environment.On prolonging the exposure time, the corrosion rate gradually decreased, the corrosion heterogeneity increased, and the dimensions of FeCO_3 crystals gradually became small. At later stages of corrosion, the corrosion current density decreased significantly and the anodic Tafel slope increased, indicating that the corrosion process was strongly inhibited. The corrosion mechanism of low-alloy steel with bainitic microstructure was proposed based on experimental results.
基金This work was supported by the National Natural Science Foundation of China(Nos.21875026,21878031)the Revitalization Talents Program of China(No.XLYC1802124)+1 种基金the Liaoning BaiQianWan Talents Program,China,the Scientific Research Fund of the Educational Department of Liaoning Province,China(No.J2019013)the Joint Research Fund of Liaoning-Shenyang National Laboratory for Materials Science,China(No.2019JH3/30100034).
文摘The Co_(3)O_(4) decorated TiO_(2) nanotube arrays(NTAs)coatings are fabricated by the combination of anodization and impregnating methods.It is found that the introduction of Co_(3)O_(4) can reduce the diffraction intensity of(101)plane of the TiO_(2) and accelerate the separation of photogenerated electron/hole pairs.In addition,the open circuit potential(OCP)and the corrosion potential of 304 stainless steel(304SS)with or without Co_(3)O_(4) decorated TiO_(2) NTAs were measured under visible light,which indicated the 304SS coupled with Co_(3)O_(4) decorated TiO_(2) NTAs had better anticorrosion performance than that of the 304SS or the 304SS coupled with pure TiO_(2) NTAs.The enhancement of the cathodic protection performance of the Co_(3)O_(4) decorated TiO_(2) NTAs can be ascribed to the matched energy levels and strong interaction between Co_(3)O_(4) and TiO_(2) NTAs,and the improvement of light absorption.
文摘A new intelligent amperometric type of electrochemical hydrogen probe to measure hydrogen atom permeation rate in the metals was devised and developed. Combined with MCS51 single slice computer system, specially programmed software was designed for data sampling, logging, storing, processing, result judgment and data output controlling. The probe is portable and can be used in both lab and in site automatically.
