The corrosion behavior of Cu-Cr alloy in 3.5%NaCl+NH3 solution had been studied, and the influences of the concentration of NH3 on corrosion resistance discussed by means of Metallograph, XRD, SEM and electrochemical ...The corrosion behavior of Cu-Cr alloy in 3.5%NaCl+NH3 solution had been studied, and the influences of the concentration of NH3 on corrosion resistance discussed by means of Metallograph, XRD, SEM and electrochemical method. The results show that the Cu is easier to corrosion than Cr, and the corrosion rate increases with the increasing of the concentration of NH3, and deformation worsen the corrosion resistance of the alloy in such corrosive environment.展开更多
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 chl...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 KCl.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 corrosion fatigue behavior of epoxy-coated Mg-3Al-1Zn alloy was investigated in air and 3.5 wt%NaCl solution. Epoxy coating as a new method was used to improve the corrosion fatigue property of the material.Result...The corrosion fatigue behavior of epoxy-coated Mg-3Al-1Zn alloy was investigated in air and 3.5 wt%NaCl solution. Epoxy coating as a new method was used to improve the corrosion fatigue property of the material.Results show that the fatigue limit（FL） of the coated specimens is higher than that of the uncoated specimens in3.5 wt% NaCl solution because of the strengthening and blocking functions of the epoxy coating. The FL of the coated specimens in 3.5 wt% NaCl solution is as high as that in air. It implies that the coated specimens are not as sensitive to the environment as the magnesium alloy. The low tensile strength and the short elongation of the pure epoxy coating lead to that the fatigue crack of the coated specimen is always initiated from the epoxy-coating film Pores and pinholes accelerate the fatigue crack initiation process. Pinholes are caused by the corrosion reactions between the epoxy coating and the NaCl solution.展开更多
文摘The corrosion behavior of Cu-Cr alloy in 3.5%NaCl+NH3 solution had been studied, and the influences of the concentration of NH3 on corrosion resistance discussed by means of Metallograph, XRD, SEM and electrochemical method. The results show that the Cu is easier to corrosion than Cr, and the corrosion rate increases with the increasing of the concentration of NH3, and deformation worsen the corrosion resistance of the alloy in such corrosive environment.
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 KCl.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financially supported by the National Natural Science Foundation of China (Nos. 51001079, 21201129, 51208333, and 51374151)Natural Science Foundation of Shanxi Province (No. 201101102002)+1 种基金the China Postdoctoral Science Foundation (No. 20100471586)the Doctoral Fund of Ministry of Education of China (No. 20091402110010)
文摘The corrosion fatigue behavior of epoxy-coated Mg-3Al-1Zn alloy was investigated in air and 3.5 wt%NaCl solution. Epoxy coating as a new method was used to improve the corrosion fatigue property of the material.Results show that the fatigue limit（FL） of the coated specimens is higher than that of the uncoated specimens in3.5 wt% NaCl solution because of the strengthening and blocking functions of the epoxy coating. The FL of the coated specimens in 3.5 wt% NaCl solution is as high as that in air. It implies that the coated specimens are not as sensitive to the environment as the magnesium alloy. The low tensile strength and the short elongation of the pure epoxy coating lead to that the fatigue crack of the coated specimen is always initiated from the epoxy-coating film Pores and pinholes accelerate the fatigue crack initiation process. Pinholes are caused by the corrosion reactions between the epoxy coating and the NaCl solution.
