The evolution process of rust layer formed on the surface of low-alloy steels in simulated marine atmospheric environment

A rust layer formed on the surface of the weathering steel sample after a 288-hour wet/dry cyclic corrosion test simulating a marine atmospheric environment. The results indicate that the degree of crystallization of the rust near the metal is poor, and corrosion products accumulate into a rust layer characterized by good adhesion and a dense structure, as observed through FIB-TEM analysis. The degree of crystallization of the corrosion products is slightly better in the band-like rust and the band-like rust achieves the secondary allocation of elements in the rust layer. Additionally, CuFeO₂ nanocrystalline formed in the band-like rust and phosphate with chromium ions is dispersed in rust near the metal exhibiting a synergistic effect in enhancing rust protection capability. This work analyzes the transformation behavior of corrosion products by characterizing the rust layer of samples subjected to indoor simulated atmospheric corrosion, thereby deepening the understanding of the evolution process of the rust layer.