Study of the potential electrochemical noise during corrosion process of aluminum alloys 2024, 7075 and pure aluminum

Abstract

AbstractProperties of the potential electrochemical noises (EN) generated during the corrosion process of aluminum alloys AA2024(T3), AA7075 (aged at 121°C/35 h + 160°C/20 h) and pure aluminum in 3wt% (mass fraction) NaCl solution were investigated in this study. During the initial stage of immersion, the EN amplitude of AA2024 is the largest while the EN amplitude of pure aluminum is negligible. The amplitude of the EN generated by these materials decreases with immersion time except the EN of AA2024 after extremely long immersion time (38 days in this study). Surface morphology corresponding to different stages of immersion and different types of EN were studied by scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) analysis. The result shows that the micro‐galvanic cells formed by the constituent particles and the alloy matrix play an important role on the corrosion process of the aluminum alloys and the EN behaviors of AA2024, AA7075 and pure aluminum is proved to be strongly related to the type and intensity of corrosion process.