Designing Weathering Steel with Optimized Mo/Ni Ratios for Better Corrosion Resistance in Simulated Tropical Marine Atmosphere.

This study investigated the corrosion resistance of weathering steels (WS) with five different Mo/Ni ratios (blank, 1:2, 1:1, 3:1, and 5:1) in a simulated tropical marine atmosphere. The results revealed that the synergistic effect between Mo and Ni with a 3:1 ratio led to the optimal atmospheric corrosion resistance of WS. Reducing Ni promotes the growth of nano-structured Fe(O,OH)₆, while increasing Mo disrupts the structure of Fe(O,OH)₆, creating additional nucleation sites for corrosion products. The evolution of the rust layer is governed by the growth of Fe(O,OH)₆ at low Mo/Ni ratios, while the destruction of Fe(O,OH)₆ by Mo becomes dominant as the Mo/Ni ratio increases. The optimized ratios (3:1) contain more α-FeOOH in the rust layer, compact the rust layer, reduce defects, and inhibit the charge transfer processes, thereby attaining better atmospheric corrosion resistance of WS. [ABSTRACT FROM AUTHOR]