Data-driven mechanistic study of Ni–Ce microalloying for enhanced corrosion resistance of weathering structural steel

In this study, outdoor exposure tests combined with corrosion big data analysis were conducted to investigate the corrosion resistance of Ni–Ce microalloyed, Cr-containing low-alloy steel in a severe marine atmosphere. The big data results show that within the first two months of corrosion, the order of corrosion resistance is as follows, 0.08Ce steel exhibits the strongest corrosion resistance, followed by 0.9Ni0.08Ce steel and 0.9Ni steel, while base metal steel shows the worst corrosion resistance. After 2 months of exposure, 0.9Ni0.08Ce steel demonstrates the strongest corrosion resistance, followed by 0.08Ce steel, 0.9Ni steel, and base metal steel in sequence. The addition of Ni and Ce significantly improves the uniform corrosion resistance of low-alloy steel, and the effect of composite addition is superior to that of single-element addition. In addition, analysis of the rust layer composition and corrosion morphology reveals that the combined action of Ni and Ce can effectively enhance the compactness of the rust layer, promote the formation of α-FeOOH and Cr₂O₃, reduce the number of cracks and pores in corrosion products, improve the stability of the rust layer, delay the corrosion process, and promote the development of low-alloy steel toward uniform corrosion. Notably, the stabilizing effect of Ce becomes significant only above a compositional threshold.