Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium ch...Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium chloride （NaCl） solutions by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, rotating disk electrode （RDE） and rotating ring-disk electrode （RRDE）. The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3.5% NaCl solution contains three reactions： dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction （ORR） is - 0.85 V vs Ag/AgCl, 3 molL^-1 KCI. The EIS results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, i.e., dissolved oxygen reduced to water.展开更多
The microstructure,elemental distribution,phase composition,and thickness of intermetallic layers between high-strength low-alloy steel(H420)/mild carbon steel(DC51)and Al–43.4Zn–1.6Si(wt.%)(galvalume,GL)alloy were ...The microstructure,elemental distribution,phase composition,and thickness of intermetallic layers between high-strength low-alloy steel(H420)/mild carbon steel(DC51)and Al–43.4Zn–1.6Si(wt.%)(galvalume,GL)alloy were comparatively investigated.The experimental results reveal that the interfacial reaction layer was composed of Fe2Al5,Fe4Al13,and Al8Fe2Si intermetallic compounds.Moreover,the growth curves of the Fe2Al5 and Fe4Al13 intermetallic layers fit the parabolic law well,and the total thickness of the intermetallic layers of H420+GL was almost the same as that of DC51+GL.However,the thickness of the Fe2Al5 layer in H420+GL was thinner than that in DC51+GL.In addition,first-principle calculations were performed to explore the effect of Mn on the growth of the Fe2Al5 intermetallic phase,and the results indicate that Mn substitution in Fe2Al5 removes electronic charge from the Al atoms,thus decreasing the thickness of the Fe2Al5 interface layer.展开更多
基金supported by the National Natural Science Foundation of China ( Grant No 40876041)Science and Technology Basic Research Program of Qingdao (Grant No 09-1-3-16-jch)the National Key Technology Research and Development Program of China (Grant No 2007 BAB27B01)
文摘Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium chloride （NaCl） solutions by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, rotating disk electrode （RDE） and rotating ring-disk electrode （RRDE）. The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3.5% NaCl solution contains three reactions： dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction （ORR） is - 0.85 V vs Ag/AgCl, 3 molL^-1 KCI. The EIS results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, i.e., dissolved oxygen reduced to water.
基金the support from Science and Technology Committee of Shanghai(Grant No.16ZR1412000)National Natural Science Foundation of China(Grant Nos.51674163 and 51104098)Guiyang Science and Technology Project(Grant No.20161001).
文摘The microstructure,elemental distribution,phase composition,and thickness of intermetallic layers between high-strength low-alloy steel(H420)/mild carbon steel(DC51)and Al–43.4Zn–1.6Si(wt.%)(galvalume,GL)alloy were comparatively investigated.The experimental results reveal that the interfacial reaction layer was composed of Fe2Al5,Fe4Al13,and Al8Fe2Si intermetallic compounds.Moreover,the growth curves of the Fe2Al5 and Fe4Al13 intermetallic layers fit the parabolic law well,and the total thickness of the intermetallic layers of H420+GL was almost the same as that of DC51+GL.However,the thickness of the Fe2Al5 layer in H420+GL was thinner than that in DC51+GL.In addition,first-principle calculations were performed to explore the effect of Mn on the growth of the Fe2Al5 intermetallic phase,and the results indicate that Mn substitution in Fe2Al5 removes electronic charge from the Al atoms,thus decreasing the thickness of the Fe2Al5 interface layer.
