Effect of Acidified Aerosols on Initial Corrosion Behavior of Q235 Carbon Steel

The effect of simulated acidified marine aerosols on the corrosion morphology of carbon steel was studied using an in situ optical stereomicroscope and scanning electron microscope equipped with an energy-dispersive spectrometer and a white-light interferometer. The morphologies of the carbon steel were identified under marine aerosols with different droplet diameters, pH, and acidifications. The results showed that corrosion was initiated in tens of seconds under aerosol droplets acidified by HCl or H2SO4. Despite the differences in the acidifier and diameter, corrosion for acidified droplets with pH > 2 was general corrosion. For acidified droplets with pH < 1, the corrosion morphology depended on the acidifier species, the ring-like morphology for HCl and ridge-like morphology for H2SO4. The segregation of Cl− was believed to be the main factor for the formation of the corrosion morphology under acidified droplets with pH < 1. Also, the concentration of SO42− in the droplets had some effect on the segregation of Cl− ions when pH < 1.