ZHU Xiaolong LIN Leyun Surface Technology Center
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General Research Institute for Nonferrous Metals
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Beijing
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110083
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ChinaTo whom correspondence should be addressed
材料科学技术（英文）
The corrosion product films of two kinds of B30 tubes(similar to CDA 715)exposed to seawat- er for various periods of time were investigated by SEM,AES and XPS.The results show that the pro- tective corrosion product film is thin,uniform and adherent.FeOOH is found to be present in the film surface,which confirms the hypothesis that iron hydroxide segregates at the surface of the film.The FeOOH promotes Ni enrichment in the corrosion layer by preventing Ni from running off.The corro- sion product film with no protectiveness is of lay- ered structure,loose and bad adherence.The for- mer film is formed through direct oxidation and the latter by precipitation and redeposition from dis- solved species.
关键词:
Cu-Ni alloy
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null
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null
F.H.Cao
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J.Q.Zhang
金属学报(英文版)
Spontaneous electrochemical noise(EN)can be a rich source of information concern-ing the processes simultaneously occurring at a corroding interface.Potential noise fluctuations during the free corrosion of pure aluminum in different concentration of neutral sodium chloride solution are investigated,and the breakdowm and restoration of passive metal's film are studied using potentiodynamic scanning(PDS)measure-ments and electrochemical impedance spectroscopy(EIS)technique.Two capacitance loops are observed in the Nyquist plots in two kinds of concentration,and the corro-sion process is under activation control at first,then become diffusion control within the oxide film and corrosion products of (Al(OH)p-mClm^-)accumulated on the surface of the corroding electrode.It is suggested that the pitting corrosion is much easier to occur for pure aluminum in 7.0wtthan in 2.0wtaCl solution,and the high concentration of chloride ion in solution inhibits the repassivation of a metastable pit.The corrosion rate deterministic step does not involve Cl^-.
关键词:
pure aluminum
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null
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null
Q. Qu
金属学报(英文版)
The regularities of atmospheric corrosion of A3 steel deposited with different amountof NaCl exposed to the air containing 1ppm SO2 at 80% RH and 25℃ were studied inlaboratory. NaCl can accelerate the corrosion of A3 steel obviously under such con-dition. The relationship between the weight loss of A3 steel and the amount of NaCldeposition can be well described by using a quadratic function. Fourier transform in-frared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopyand electron dispersion X-ray analysis (SEM/EDAX) were used to characterize thecorrosion products. In the absence of NaCl, FeSO4 xH2O is the dominant corro-sion products, while Fe3O4, FeSO4@ H2O, β-FeOOH and γ-FeOOH dominate in thepresence of NaCl.
关键词:
A3 steel
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null
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null
