Comparative study on the atmospheric corrosion behavior of Nb- and Sb-added weathering steels exposed to the South China Sea

The atmospheric corrosion behavior of new-type weathering steels (WSs) was comparatively studied, and the effects of Nb and Sb during corrosion were clarified in detail through field exposure and characterization. The results showed that the addition of Nb and Sb played positive roles in corrosion resistance, but there was a clear difference between these two elements. Nb addition slightly improved the rust property of conventional WS but could not inhibit the electrochemical process. In contrast, Sb addition significantly improved the corrosion resistance from the aspects of electrochemistry and rust layer. Specifically, 0.05% Sb optimized the rust structure, accelerated the formation of a high proportion of dense and protective α-FeOOH, repelled the invasion of Cl^-, and retarded localized acidification at the bottom of the pit.