No abstract

The atmospheric corrosion behavior of antirust aluminum alloys 3A21 and 5A05 in industrial and coastal atmospheres was investigated and compared. Weight loss results, together with corrosion morphology characterization, suggest that the coastal atmosphere is much more corrosive to antirust aluminum than the industrial atmosphere. 5A05 alloy has better localized corrosion resistance than 3A21 alloy, and the corrosion rate shows a decreasing tendency with exposure time. After 3 years of exposure, the antirust aluminum samples only suffer pitting corrosion attack and retain their mechanical properties well. In the two atmospheres, the corrosion products are mainly oxides, aluminum hydroxychloride, aluminum sulfate hydrate, and basic aluminum sulfate. Besides, the atmospheric corrosion mechanism and the corrosion comparison between the two atmospheres were also discussed.

The atmospheric corrosion behavior of 6061 aluminum alloy exposed in industrial and marine atmosphere environments for 36 months has been investigated by weight loss test, tensile strength test, X‐ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and optical microscope. The results of weight loss and tensile strength showed that, compared with industrial atmosphere environment, 6061 presented higher corrosion susceptibility in marine atmosphere environment. XPS analysis indicated that the major constituents of corrosion products formed in industrial atmosphere environment were aluminum hydroxide, aluminum oxide, and aluminum sulfate. In marine atmosphere environment, corrosion products mainly contained aluminum chloride, aluminum hydroxide, and aluminum oxide. Surface morphologies analysis revealed that the corrosion products formed in industrial atmosphere environment were agglomerated and uneven. The corrosion products formed in marine atmosphere environment presented polygon shape, and revealed some broad cracks. Cross‐section morphologies analysis manifested that 6061 suffered pitting attack in both types of atmosphere environments, and the intensity of pitting attack in marine atmosphere environment was much more serious than that in industrial atmosphere environment.

The atmospheric corrosion behaviour of 30CrMnSiA high-strength steel exposed in rural, industrial and marine atmosphere environments in China for 60 months was investigated in virtue of the weight loss, X-ray diffractometer (XRD), scanning electron microscope (SEM) and grey relational analysis. The results showed that 30CrMnSiA high-strength steel exhibited the highest corrosion susceptibility and the lowest corrosion susceptibility in marine atmosphere environment and rural atmosphere environment, respectively. Lepidocrocite and goethite were found as the major constituents of the rust layer in three types of atmosphere environments, and akaganeite was also detected in marine atmosphere environment. The rust layer exhibited the tendency of flaking away from the substrate and becoming dense in marine atmosphere environment and rural atmosphere environment, respectively. Grey relational analysis demonstrated that, among a variety of environmental factors, the airborne sea-salt was the primary factor influencing the atmospheric corrosion of 30CrMnSiA high-strength steel.