Z. Zhang
,
C. Cai
,
F.H. Cao
,
Z.N. Gao
,
J.Q. Zhang
,
C.N. Cao
金属学报(英文版)
The corrosion behavior of pure aluminum in neutral 3.0% (mass fraction) sodium chloride (NaCl) solution has been studied using electrochemical impedance spectroscopy (EIS) measurement in conjunction with the scanning electron microscopy (SEM) technique. EIS information on the evolution of pitting corrosion over a period of 15 days has been obtained and analyzed with equivalent circuit technique. The results shown that, during the ensemble constant immersion time, two time constants involved, the high frequency one originated from the protective layer on the corroding surface while the low frequency one from the diffusion process or the corrosion reaction and so on. And there existed a period for oxide film to growth and thickening prior to the commencement of the attacking of chloride ions to the substrate. Meanwhile, good relationship between EIS and the material corrosion type / severity has been obtained, which has been interpreted according to the characteristics of corrosion process such as auto acceleration of pitting corrosion and the protection of local anodic reaction to the area around them.
关键词:
pure aluminum
,
null
,
null
C.S. Wu
,
Z. Zhang
,
F.H. Cao
金属学报(英文版)
The influence of chloride or sulphur dioxide on the corrosion behavior of copper tube
in the air-conditioning system was studied using scanning electron microscope (SEM),
energy dispersion spectrometer (EDS) and cyclic polarization techniques. The results
showed that the corrosion of copper tube are mainly caused by the SO4 and Cl ions
in the circulating water, and the former is mainly responsible for the general corrosion
of the copper tube whilst the latter for the pitting corrosion. The di®erent in°uences
of SO4 and Cl ions on the corrosion type of copper tube may be attributed to that
the radius of SO4 ion is much larger than that of Cl ion. Meanwhile the results
also indicated that SO4 inhibits the pitting corrosion caused by Cl and Cl inhibits
the general corrosion initiated by SO4 due to their competitive adsorption on the
copper matrix.
关键词:
copper
,
null
,
null
