A laboratory study of the atmospheric corrosion of carbon steel deposited with (NH4)2SO4 in the presence of SO2 is reported. The different levels of (NH4)2SO4 (0, 15, 30, 45, 60 μg·cm-2) were added on the surfac...A laboratory study of the atmospheric corrosion of carbon steel deposited with (NH4)2SO4 in the presence of SO2 is reported. The different levels of (NH4)2SO4 (0, 15, 30, 45, 60 μg·cm-2) were added on the surface of the samples before the exposure. The corrosion was investigated by a combination of gravimetry, Fourier transform infrared spectroscope and scanning electron microscopy. A detailed knowledge about the corrosion products was acquired, both quantitatively and qualitatively. The results show that the metal loss increased and the increasing tendency of corrosion rates slowed down with the increasing exposure time. The phase constituents of the corrosion products are mainly α-FeO(OH), γ-FeO(OH), and δ-FeO(OH).展开更多
The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans （T.f） and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. Th...The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans （T.f） and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential （Eocp） and electrochemical impedance spectroscopy （EIS） of the steel A3 electrodes were measured in leathen culture medium without and with T.f （simply called T.f solution in the following paper） in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy （SEM） transformed from solid globules to tabular plates and to spongy globules and plates.展开更多
The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A...The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A3 steel obviously under such condition. The relationship between the weight loss of A3 steel and the amount of NaCl deposition can be well described by using a quadratic function. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy and electron dispersion X-ray analysis (SEM/EDAX) were used to characterize the corrosion products. In the absence of NaCl, FeSO4 · xH2O is the dominant corrosion products, while Fe3O4, FeSO4·H2O, β-FeOOH and γ-FeOOH dominate in the presence of NaCl.展开更多
Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of...Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of NaCI deposition increases with the exposure time, which can be correlated by using exponential decay function. The relationship between dry mass gain and amount of NaCI deposition at a certain exposure time follows a quadratic function. More amount of NaCI deposition will slow down the corrosion rate to some extent after exposure for a certain time. SEM/EDAX was used to characterize the corrosion surface and products. The surfaces of the NaCI treated A3 steel were obviously uneven, and some tiny crevices appear in the corrosion products that could help O2 transmit to the inner layer. The amount of oxygen in atomic percentage in the corrosion products increases with the amount of NaCI deposition.展开更多
文摘A laboratory study of the atmospheric corrosion of carbon steel deposited with (NH4)2SO4 in the presence of SO2 is reported. The different levels of (NH4)2SO4 (0, 15, 30, 45, 60 μg·cm-2) were added on the surface of the samples before the exposure. The corrosion was investigated by a combination of gravimetry, Fourier transform infrared spectroscope and scanning electron microscopy. A detailed knowledge about the corrosion products was acquired, both quantitatively and qualitatively. The results show that the metal loss increased and the increasing tendency of corrosion rates slowed down with the increasing exposure time. The phase constituents of the corrosion products are mainly α-FeO(OH), γ-FeO(OH), and δ-FeO(OH).
文摘The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans （T.f） and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential （Eocp） and electrochemical impedance spectroscopy （EIS） of the steel A3 electrodes were measured in leathen culture medium without and with T.f （simply called T.f solution in the following paper） in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy （SEM） transformed from solid globules to tabular plates and to spongy globules and plates.
基金This work was financially supported by the National Natural Science Foundation of China (Project No. 59899144). The authors are grateful to Ms Wang for English diction.
文摘The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A3 steel obviously under such condition. The relationship between the weight loss of A3 steel and the amount of NaCl deposition can be well described by using a quadratic function. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy and electron dispersion X-ray analysis (SEM/EDAX) were used to characterize the corrosion products. In the absence of NaCl, FeSO4 · xH2O is the dominant corrosion products, while Fe3O4, FeSO4·H2O, β-FeOOH and γ-FeOOH dominate in the presence of NaCl.
基金This work was financially supported by the National Natural Science Foundation of China. The number of the project is 5989914. The authors are grateful to Ms. Ping Wan for English diction.
文摘Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of NaCI deposition increases with the exposure time, which can be correlated by using exponential decay function. The relationship between dry mass gain and amount of NaCI deposition at a certain exposure time follows a quadratic function. More amount of NaCI deposition will slow down the corrosion rate to some extent after exposure for a certain time. SEM/EDAX was used to characterize the corrosion surface and products. The surfaces of the NaCI treated A3 steel were obviously uneven, and some tiny crevices appear in the corrosion products that could help O2 transmit to the inner layer. The amount of oxygen in atomic percentage in the corrosion products increases with the amount of NaCI deposition.
