Study on the Effect of Dry and Wet Cycle Time Ratio on the Corrosion Behavior of 2198 Aluminum–Lithium Alloy

Abstract

The corrosion of 2198 aluminum–lithium alloy in a marine atmospheric environment was simulated using a wet–dry alternating experimental setup. Weight-loss measurement methods, electrochemical impedance spectroscopy (EIS), scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), macroscopic morphology testing, three-dimensional morphology testing, and X-ray photoelectron spectroscopy (XPS) were used to study the wet–dry alternating corrosion behaviors and mechanisms of 2198 aluminum–lithium alloys under simulated marine atmospheric environment. The results indicate that corrosion weight loss increases with decreasing wet-to-dry ratios, accompanied by an increase in the corrosion rate. Various data suggest that the primary corrosion products are composed of Al₂O₃, AlO(OH), and AlCl₃. The reduction in the wet-to-dry ratio leads to the enrichment of Cl⁻ within the corrosion products, extending the contact time between the substrate and the medium, thereby intensifying the hydrolysis of Al³⁺. This exacerbates the dissolution at pitting sites, which in turn erodes and breaks down the corrosion product film, accelerating the overall corrosion process.