Effect of Nickel Content on Rust Evolution for Weathering Steels

摘要

In order to understand the effect of Ni content on rust evolution for weathering steels at marine atmosphere,three types of steels containing different Ni content were prepared for alternate wet-dry accelerated corrosion test.Rust layer patterns and characteristics of the steels were investigated by using XRD,EMPA and electrochemical experiments.The results show that the corrosion resistance of the steels is improved with Ni content increasing.The patterns of inner rust layers are different from that of outer rust layers,and the rust compactness increases with Ni content increasing.Crystal phases are mainly composed of Fe3O4,γ–FeOOH,α-FeOOH and β–FeOOH in the rust layer.The distribution of Ni is uniform inside the rust layers,but Cu is enriched in rust layers.The Ni content in the steels has little effect on cation-selective property while the steels containing Ni content less than 1.5 percent.The ratio of Ni content of rust layer and steel is around 0.53-0.75.