A study of the evolution of rust on Mo–Cu-bearing fire-resistant steel submitted to simulated atmospheric corrosion

The corrosion evolution of a Mo–Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated by corrosion weight gain, XRD, EPMA, XPS, and polarization curves. The results indicate that the corrosion kinetics is closely related to the rust composition and electrochemical properties. As the corrosion proceeds, the relative content of γ-FeOOH and Fe3O4 decreases and α-FeOOH increases, and the rust layer becomes compact and adherent to steel substrate. Molybdenum and copper enrich in the inner rust layer, especially at the bottom of the corrosion nest, forming non-soluble molybdate and Cu(I)-bearing compounds responsible for enhanced corrosion resistance of the rust layer.

► The rusting evolution of a Mo–Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated.
► The rusting evolution of the steel is related to the rust composition, structure, and electrochemical characteristics.
► Increased content of α-FeOOH and decreased γ-FeOOH and Fe3O4 indicate the enhanced resistance of the rust.
► Mo and Cu are involved in the formation of molybdate and Cu(I)-bearing compounds in the rust.