Corrosion Behavior of Weathering Steel in Atmospheric Environment Containing Fine Particulate Matter and the Influence of Stabilization Treatment

The corrosion behavior of weathering steel Q345qENH exposed to an atmospheric environment rich in fine particulate matter Northwest China for 3 y was studied. The effects of stabilization treatment (treatment method to accelerate the formation of stable rust layer on the surface) on the kinetic curves of the sample, the structure and physical phases, and the electrochemical properties of the rust layer were analyzed. The long-term corrosion tendency of the two samples was predicted by the kinetic model. The results show that the corrosion rate of stabilized samples is greater than that of the untreated before 1 y, and the result is opposite after 1 y. In addition to α-FeOOH, γ-FeOOH, Fe₂O₃, and Fe₃O₄, the rust layer also contains a large amount of SiO₂. The resistance of the rust layer of the stabilized sample is 1.25 and 1.06 times higher than that of the untreated sample at 12 and 36 month of corrosion, respectively. In that environment, corrosion products nucleate with SiO₂ as the base and encapsulate the soil dust to form particles of different sizes, which leads to poor bonding within the rust layer. The stabilization treatment improves the physical barrier effect of the rust layer, reduces the adhesion of SiO₂ inside, and promotes the formation of a dense rust layer.