Exploring Corrosion Protection Evolution of Rust Layer on High-Cr-content Weathering Bridge Steel in Simulated Tropical Marine Atmosphere

Rust layer is the critical factor that determines the corrosion resistance performance of weathering bridge steel. Clarifying the evolution mechanism of rust layer is fundamental for the design and optimization of weathering bridge steel. In this study, we investigate the evolution of rust layer on high-Cr-content weathering bridge steel combined with atmospheric corrosion monitoring (ACM) sensor and big data mining technique in simulated tropical marine atmosphere. Thereby, we found that the trend of changes in the protective properties of the rust layer is a periodic pattern of ‘ascending-constant’, instead of continuous ascending. Correlation analysis indicates that the phenomenon is caused by the introduction of Cr element, which promotes the formation of FeCr2O4 in the rust layer. FeCr2O4 can prevent chloride ions from entering the rust layer, exerting a protective effect. The findings provide a strong scientific foundation for designing and enhancing new high-Cr-content weathering bridge steel.