Effect of Cu on corrosion resistance performance of bridge weathering steels

Corrosion resistance performance of Cu-containing bridge weathering steels under marine atmosphere was studied by cyclic wet/dry corrosion test and the effect of Cu on the rust layer was also investigated by XRD and SEM method. The results showed that,the corrosion depths and corrosion rates both decreased with the increase of Cu in the experimental steels.The corrosion rates increased quickly before 48 h then kept constant and after 96 h decreased with corrosion time.The crystalline constituents of the rust layer evolved with corrosion time.Initially,the rust layer was roughly composed of Fe3O4 and γ-FeOOH which changed to Ni(0.6~1)Fe(2.4~2)O4,α-FeOOH and γ-FeOOH in the middle of the corrosion process.The rust eventually consisted of Ni(0.6~1)Fe(2.4~2)O4,α-FeOOH,γ-FeOOH and Fe3O4 in minor fraction.