A study for corrosion behavior of a new-type weathering steel used in harsh marine environment

The effect of Mn on corrosion resistance of Ni-advanced weathering steel in a solution simulating the South China Sea atmosphere were studied by dry-wet cyclic test, electrochemical techniques, morphology characterization and component analysis. The results show that the increase of Mn content in the Ni-advanced weathering steel is detrimental to its corrosion resistance. Increase of Mn content in the steel has little influence on the microstructure but leads to the difference of rust film formed on the weathering steels. Mn is preferentially corroded in the simulated solution and primarily exists as MnO/MnO₂ particles in the rust, which not only accelerate the generation of iron oxides, but also affect the relative proportions of different iron compounds. The rust film of Ni advanced weathering steel with higher Mn content has lower α/γ* ratio.