EFFECT OF ION SELECTIVE PROPERTY ON PROTECTIVE ABILITY OF RUST LAYER FORMED ON WEATHERING STEEL EXPOSED IN THE MARINE ATMOSPHERE

The ion selective properties of the rust film was studied in order to elucidate the mechanism of the protective ability of the stable rust farer formed on the weathering steel made by Baosteel Group Corporation. Results show that the film made of α-FeOOH or γ-FeOOH has the cation selective ability, while the film made of α-CrxFe1-xOOH has the ion selective ability. Therefore, the Cl- is restricted to pass freely through the rust layer on the weathering steel. During corrosion, the exirichment of alloying elements was observed in the inner rust layer and the exterior part of the weathering steel exposed at the coast of Qingdao city for 4 a.