Optimization of Mo on the corrosion resistance of Cr-advanced weathering steel designed for tropical marine atmosphere

The effect of Mo on the corrosion resistance of Cr-advanced weathering steel designed for the tropical marine atmosphere was studied through the morphology characteristics, element distribution, phase composition and electrochemical characteristics of the corrosion products. The results indicated that Mo mainly forms nano-sized MoO₂ and MoO₃, which destroy the network structure of Fe(O, OH)₆, and provide more nucleation sites for newly formed corrosion products, thereby promoting the conversion of γ-FeOOH to α-FeOOH. Mo also promotes the conversion of CrO₃ in the corrosion products to more stable and corrosion resistant Cr₂O₃ and Fe₂CrO₄. In addition, Mo promotes the enrichment of Cu in the form of Cu and Cu₂O at the interface between the corrosion product layer and the substrate. The comprehensive effect of Mo makes the corrosion product layer show more excellent stability and compactness, effectively inhibit the invasion of Cl⁻, so the corrosion resistance of 0.1Mo steel is improved.