The anodic behavior of cerium （Ce） in A1C13-1-ethyl-3-methyl-imidazolium chloride （A1CI3-EMIC） ionic liquid has been investigated. Linear sweep voltammetry （LSV）, electrochemical impedance spectra （EIS）, Raman...The anodic behavior of cerium （Ce） in A1C13-1-ethyl-3-methyl-imidazolium chloride （A1CI3-EMIC） ionic liquid has been investigated. Linear sweep voltammetry （LSV）, electrochemical impedance spectra （EIS）, Raman spectra, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS） were carried out to state the process and mechanism during anodic reaction. The results show that Ce can be electrochemically oxidized and dissolved in the ionic liquid. The oxide film of Ce markedly affects its anodic behavior by blocking the dissolution of the underlying metal. Moreover. the dissolution of metal surface brings about the stripping of the oxide film on Ce, thus leading to an oxide free surface. This work demonstrates a theoretical foundation for electrolytic etching of Ce in ionic liquids,展开更多
The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture featur...The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture features of solid–solution and peak-aged steels.Aging precipitation exerts a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and oth-er phases or interfaces.The strength of the martensite matrix is enhanced by abundant and evenly dispersed Ni(Fe,Al)precipitates,thereby reducing the possibility of splitting across martensite laths.Meanwhile,the Volta potential difference(VPD)between the matrix and primary NbC particles increases from 11.43 to 18.60 mV.Given that most of the primary NbC particles tend to be distributed along high-angle grain boundaries(HAGBs),anodic dissolution along HAGBs accelerates.Therefore,mechanical and electrochemical factors triggered by aging precipitation are involved in the variation in SCC behavior and mechanism.The SCC susceptibility of the steel in-creases along with the increasing tendency for intergranular cracking.展开更多
Zinc is common metal used for steel protection from corrosion.The addition of further element,such as Ni,can modify the corrosion rate and maintain sacrificial protection.The anodic dissolution behavior of Zn,Ni and Z...Zinc is common metal used for steel protection from corrosion.The addition of further element,such as Ni,can modify the corrosion rate and maintain sacrificial protection.The anodic dissolution behavior of Zn,Ni and Zn-Ni alloys with different Ni contents（from 0.5% to 10%,mass fraction） in 3.5% Na Cl solution was investigated using potentiodynamic,potentiostatic and galvanostatic techniques.The composition and microstructure of the corrosion layer on Zn,Ni and Zn-Ni alloys were characterized by energy-dispersive X-ray spectroscopy analysis（EDX） and scanning electron microscopy（SEM）.The galvanostatic curves show that the anodic behavior of all investigated electrodes exhibits active/passive transition and the tendency of the alloys to passivity decreases with the increase in Ni content,except for 99.5Zn-0.5Ni alloy.While the potentiodynamic curves exhibit active passive transition only for pure Zn.Surface analysis reveals the presence of oxides,chlorides and metal hydroxide chloride in corrosion products,and very small cracks are observed for 90Zn-10 Ni alloy compared with that of Zn.展开更多
The addition of phosphoric acid into sulfuric acid solution is mentioned to be helpful in the reduction of sulfation after deep discharge of lead-acid battery. The anodic behavior of Pb and Pb?In alloys was studied in...The addition of phosphoric acid into sulfuric acid solution is mentioned to be helpful in the reduction of sulfation after deep discharge of lead-acid battery. The anodic behavior of Pb and Pb?In alloys was studied in pure phosphoric acid and sulfuric acid containing various concentrations of phosphoric. The electrochemical measurements were performed using potentiodynamic, potentiostatic and cyclic voltammetric techniques. The composition and morphology of passive layer formed on the surfaces of Pb and Pb?In alloys were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy analysis (EDX) and scanning electron microscopy (SEM). The potentiodynamic study shows that the passive current density increases with increasing the indium content in the alloy in the examined solutions. The addition of 0.1 mol/L H3PO4 into theelectrolyte is more effective to decrease the thickness of passive film on the surface of alloys containing higher indium content (10% and 15%). The XRD, EDX and SEM data reveal that the formation of PbSO4 and PbO on the surface decreases with increasing the indium level in the alloy and is completely prevented at higher indium content (15%) in mixed acid.展开更多
Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is cons...Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.展开更多
基金Project supproted by Discipline Development Foundation of China Academy of Engineering and Physics(2015B0301065)
文摘The anodic behavior of cerium （Ce） in A1C13-1-ethyl-3-methyl-imidazolium chloride （A1CI3-EMIC） ionic liquid has been investigated. Linear sweep voltammetry （LSV）, electrochemical impedance spectra （EIS）, Raman spectra, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS） were carried out to state the process and mechanism during anodic reaction. The results show that Ce can be electrochemically oxidized and dissolved in the ionic liquid. The oxide film of Ce markedly affects its anodic behavior by blocking the dissolution of the underlying metal. Moreover. the dissolution of metal surface brings about the stripping of the oxide film on Ce, thus leading to an oxide free surface. This work demonstrates a theoretical foundation for electrolytic etching of Ce in ionic liquids,
基金support from the National Key Research and Development Program of China(No.2023YFB3710300)National Natural Science Foundation of China(Nos.12174296 and 52101088)+1 种基金Major Program(JD)of Hubei Province,China(No.2023BAA019-5)Numerical calculation is supported by the High-Performance Computing Center of Wuhan University of Science and Technology,China.
文摘The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture features of solid–solution and peak-aged steels.Aging precipitation exerts a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and oth-er phases or interfaces.The strength of the martensite matrix is enhanced by abundant and evenly dispersed Ni(Fe,Al)precipitates,thereby reducing the possibility of splitting across martensite laths.Meanwhile,the Volta potential difference(VPD)between the matrix and primary NbC particles increases from 11.43 to 18.60 mV.Given that most of the primary NbC particles tend to be distributed along high-angle grain boundaries(HAGBs),anodic dissolution along HAGBs accelerates.Therefore,mechanical and electrochemical factors triggered by aging precipitation are involved in the variation in SCC behavior and mechanism.The SCC susceptibility of the steel in-creases along with the increasing tendency for intergranular cracking.
文摘Zinc is common metal used for steel protection from corrosion.The addition of further element,such as Ni,can modify the corrosion rate and maintain sacrificial protection.The anodic dissolution behavior of Zn,Ni and Zn-Ni alloys with different Ni contents（from 0.5% to 10%,mass fraction） in 3.5% Na Cl solution was investigated using potentiodynamic,potentiostatic and galvanostatic techniques.The composition and microstructure of the corrosion layer on Zn,Ni and Zn-Ni alloys were characterized by energy-dispersive X-ray spectroscopy analysis（EDX） and scanning electron microscopy（SEM）.The galvanostatic curves show that the anodic behavior of all investigated electrodes exhibits active/passive transition and the tendency of the alloys to passivity decreases with the increase in Ni content,except for 99.5Zn-0.5Ni alloy.While the potentiodynamic curves exhibit active passive transition only for pure Zn.Surface analysis reveals the presence of oxides,chlorides and metal hydroxide chloride in corrosion products,and very small cracks are observed for 90Zn-10 Ni alloy compared with that of Zn.
文摘The addition of phosphoric acid into sulfuric acid solution is mentioned to be helpful in the reduction of sulfation after deep discharge of lead-acid battery. The anodic behavior of Pb and Pb?In alloys was studied in pure phosphoric acid and sulfuric acid containing various concentrations of phosphoric. The electrochemical measurements were performed using potentiodynamic, potentiostatic and cyclic voltammetric techniques. The composition and morphology of passive layer formed on the surfaces of Pb and Pb?In alloys were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy analysis (EDX) and scanning electron microscopy (SEM). The potentiodynamic study shows that the passive current density increases with increasing the indium content in the alloy in the examined solutions. The addition of 0.1 mol/L H3PO4 into theelectrolyte is more effective to decrease the thickness of passive film on the surface of alloys containing higher indium content (10% and 15%). The XRD, EDX and SEM data reveal that the formation of PbSO4 and PbO on the surface decreases with increasing the indium level in the alloy and is completely prevented at higher indium content (15%) in mixed acid.
基金Projects (50804010, 51074046) supported by the National Natural Science Foundation of China
文摘Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.
