PNNL

Abstract

The time-dependent corrosion behavior of pure aluminum (Al) in chloride containing environment was investigated using various electrochemical and characterization techniques for up to 336 hours. Transmission electron microscopic and secondary ion mass spectroscopic analysis revealed the continuous dissolution of the surface film over the immersion time. In the meantime, the passive oxide layer thickness increment resulted in the surface film resistance enhancement over the immersion time, as indicated by the electrochemical impedance spectroscopic analysis. The electrochemical noise measurements exhibited increased corrosion kinetics over the immersion until 60 hours because of the accelerated localized corrosion in the early stage of immersion. However, controlled corrosion kinetics have been observed over long hours of immersion due to the corrosion product's deposition inside the permanent pits.