The passive film formed on 2205 duplex stainless steel（DSS） in 0.5 M NaHCO3＋0.5 M NaCl aqueous solution was characterized by electrochemical measurements,including potentiodynamic anodic polarization and dynamic el...The passive film formed on 2205 duplex stainless steel（DSS） in 0.5 M NaHCO3＋0.5 M NaCl aqueous solution was characterized by electrochemical measurements,including potentiodynamic anodic polarization and dynamic electrochemical impedance spectroscopy（DEIS）.The results demonstrate that there is a great difference between the passive film evolutions of ferrite and austenite.The impedance values of ferrite are higher than those of austenite.The impedance peaks of ferritic and austenitic phases correspond to the potential of 0.15 and 0.25 V in the low potential range and correspond to 0.8 and 0.75 V in the high potential range.The evolutions of the capacitance of both phases are reverse compared to the evolutions of impedance.The thickness variations obtained from capacitance agree well with those of impedance analysis.The results can be used to explain why pitting corrosion occurs more easily in austenite phase than in ferrite phase.展开更多
Pitting corrosion of 316L stainless steel in NaCl solution was investigated by means of staircase potential electrochemical impedance spectroscopy（SPEIS）.The investigation focused on the transition of stainless stee...Pitting corrosion of 316L stainless steel in NaCl solution was investigated by means of staircase potential electrochemical impedance spectroscopy（SPEIS）.The investigation focused on the transition of stainless steel from the passive state to pitting corrosion.Based on the evolution of electrical parameters of the equivalent electrical circuit,it is suggested that the most probable mechanism of pit creation is the film breaking model.The result demonstrates that staircase potential electrochemical impedance spectroscopy is an effective method for the investigation of pitting corrosion.展开更多
The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy（EIS） and Mott-Schottky analysis.The chemical compositions of the hot growth...The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy（EIS） and Mott-Schottky analysis.The chemical compositions of the hot growth films were detected by X-ray photoelectron spectroscopy（XPS）.The results show that the transfer resistance and film resistance increase with increasing temperature to 400℃,then they decrease sharply with further continuously increasing temperature.Formation time plays an important role in determining the electron properties of the hot growth film,when formation time reaches to 1 d,the transfer resistance and film resistance reach to the maximum value.Hot growth film has better anticorrosion behaviour in bicarbonate/carbonate solution containing chloride ions or sulfide ions.Mott-Schottky analysis reveals that hot growth film has n-p type semi-conductive property.XPS results show that the hot growth film is mainly composed of the inner chromium oxide and the outer iron oxide.展开更多
The effect of solution pH,Cl;concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscop...The effect of solution pH,Cl;concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscopy and X-ray photoelectron spectroscopy.The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0,below which the anodic polarization curves of the steel are actively dissolved.The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl;concentration and solution temperature.Pits are initiated on the sample surface in the presence of the Cl;and gradually developed into uniform corrosion with increasing the Cl;concentrations.Moreover,the corrosion is more serious with an increase in solution temperature.展开更多
基金supported by the National Natural Science Foundation of China(No.50871020)
文摘The passive film formed on 2205 duplex stainless steel（DSS） in 0.5 M NaHCO3＋0.5 M NaCl aqueous solution was characterized by electrochemical measurements,including potentiodynamic anodic polarization and dynamic electrochemical impedance spectroscopy（DEIS）.The results demonstrate that there is a great difference between the passive film evolutions of ferrite and austenite.The impedance values of ferrite are higher than those of austenite.The impedance peaks of ferritic and austenitic phases correspond to the potential of 0.15 and 0.25 V in the low potential range and correspond to 0.8 and 0.75 V in the high potential range.The evolutions of the capacitance of both phases are reverse compared to the evolutions of impedance.The thickness variations obtained from capacitance agree well with those of impedance analysis.The results can be used to explain why pitting corrosion occurs more easily in austenite phase than in ferrite phase.
文摘Pitting corrosion of 316L stainless steel in NaCl solution was investigated by means of staircase potential electrochemical impedance spectroscopy（SPEIS）.The investigation focused on the transition of stainless steel from the passive state to pitting corrosion.Based on the evolution of electrical parameters of the equivalent electrical circuit,it is suggested that the most probable mechanism of pit creation is the film breaking model.The result demonstrates that staircase potential electrochemical impedance spectroscopy is an effective method for the investigation of pitting corrosion.
基金Supported by the National Basic Research Program of China(No.2007CB707702)
文摘The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy（EIS） and Mott-Schottky analysis.The chemical compositions of the hot growth films were detected by X-ray photoelectron spectroscopy（XPS）.The results show that the transfer resistance and film resistance increase with increasing temperature to 400℃,then they decrease sharply with further continuously increasing temperature.Formation time plays an important role in determining the electron properties of the hot growth film,when formation time reaches to 1 d,the transfer resistance and film resistance reach to the maximum value.Hot growth film has better anticorrosion behaviour in bicarbonate/carbonate solution containing chloride ions or sulfide ions.Mott-Schottky analysis reveals that hot growth film has n-p type semi-conductive property.XPS results show that the hot growth film is mainly composed of the inner chromium oxide and the outer iron oxide.
基金financially sponsored by the National Basic Research Program of China(2014CB643306)
文摘The effect of solution pH,Cl;concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscopy and X-ray photoelectron spectroscopy.The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0,below which the anodic polarization curves of the steel are actively dissolved.The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl;concentration and solution temperature.Pits are initiated on the sample surface in the presence of the Cl;and gradually developed into uniform corrosion with increasing the Cl;concentrations.Moreover,the corrosion is more serious with an increase in solution temperature.
