Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectros...Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectroscopy, and SEM micrograph analysis. Samples of different times up to 240 h were tested during exposure. Corrosion product was primarily composed of Fe（Ca, Mg）（CO3 ）2, which was distinguished by two layers. With an increase in the exposure time, the charge transfer resistance and polarization resistance increased progressively, the uniform cor- rosion rate decreased, and the corrosion reaction was controlled by the diffusion process instead of the activation process. All phenomena were attributed to the formation of the protective corrosion product layer. More compact and lower porosity of the layer made it more difficult to transfer and diffuse through the corrosion product layer for the charges and ions. Similar results were obtained bv electrochemical test and mass-loss experiment.展开更多
The in situ spectroelectrochemical experiment shows that an absorption peak at 580.5 nm attributable to poly(methylene blue) grows slowly at the beginning of the electrolysis of methylene blue, and then this peak grow...The in situ spectroelectrochemical experiment shows that an absorption peak at 580.5 nm attributable to poly(methylene blue) grows slowly at the beginning of the electrolysis of methylene blue, and then this peak grows more quickly. The visible spectra prove that there are two absorption peaks at 580.5 and 690.2 nm respectively for the mixture solution after electrolysis. The former one indicates that poly(methylene blue)polymerized on the ITO electrode is partly soluble; the latter one is attributed to a water-soluble polymer since it completely dissolves in the aqueous solution. The result from the rotating ring-disk electrode identifies that an intermediate is produced at the disk electrode, which is collected at the ring electrode. The ring current increases with decreasing the ring potential and with increasing the rotation rate. Thus, the intermediate is a species carrying a positive charge and not too stable.The result from the XPS experiment shows that the anions can be doped into poly(methylene blue) film and dedoped from it during oxidation and reduction processes. The results from the impedance experiment indicate that the charge transfer impedance of poly(methylene blue) decreases with decreasing potential.展开更多
基金Item Sponsored by Program for New Century Excellent Talents in University of the Ministry of Education of China(NCET-07-0686)
文摘Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectroscopy, and SEM micrograph analysis. Samples of different times up to 240 h were tested during exposure. Corrosion product was primarily composed of Fe（Ca, Mg）（CO3 ）2, which was distinguished by two layers. With an increase in the exposure time, the charge transfer resistance and polarization resistance increased progressively, the uniform cor- rosion rate decreased, and the corrosion reaction was controlled by the diffusion process instead of the activation process. All phenomena were attributed to the formation of the protective corrosion product layer. More compact and lower porosity of the layer made it more difficult to transfer and diffuse through the corrosion product layer for the charges and ions. Similar results were obtained bv electrochemical test and mass-loss experiment.
文摘The in situ spectroelectrochemical experiment shows that an absorption peak at 580.5 nm attributable to poly(methylene blue) grows slowly at the beginning of the electrolysis of methylene blue, and then this peak grows more quickly. The visible spectra prove that there are two absorption peaks at 580.5 and 690.2 nm respectively for the mixture solution after electrolysis. The former one indicates that poly(methylene blue)polymerized on the ITO electrode is partly soluble; the latter one is attributed to a water-soluble polymer since it completely dissolves in the aqueous solution. The result from the rotating ring-disk electrode identifies that an intermediate is produced at the disk electrode, which is collected at the ring electrode. The ring current increases with decreasing the ring potential and with increasing the rotation rate. Thus, the intermediate is a species carrying a positive charge and not too stable.The result from the XPS experiment shows that the anions can be doped into poly(methylene blue) film and dedoped from it during oxidation and reduction processes. The results from the impedance experiment indicate that the charge transfer impedance of poly(methylene blue) decreases with decreasing potential.
