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
Q. Qu
,
C.W. Yan
,
L. Li
,
L. Zhang
,
G.H. Liu
,
C.N. Cao
金属学报(英文版)
Influence of NH4Cl on the initial atmospheric corrosion of zinc was investigated via
quartz crystal microbalance (QCM) in laboratory at 80%RH and 25℃. The results
show that NH4Cl can accelerate the initial corrosion of zinc. Mass gain increase with
the exposure time, but mass gain in the later doesn't change obviously due to the
formation of the insoluble simonkolleite on zinc surface in the presence of NH4Cl.
Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) was
used to characterize the corrosion products. Zn5Cl2(OH)8·H2O, (NH4)2ZnCl4 and
ZnO are the corrosion products on zinc. Brief discussion on the mechanisms of atmospheric corrosion of zinc in the presence of NH4Cl was introduced.
关键词:
atmospheric corrosion
,
null
,
null
