Kinetic Behavior of Q235 Steel at Initial Stage of Corrosion in Simulated Atmosphere

The kinetic behavior of Q235 steel at initial stage of corrosion in simulated atmosphere was studied by cyclic corrosion test. The corrosion products were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The three-dimensional corrosion morphology was observed by laser scanning confocal microscopy (LSCM), and the relationships between several kinetic parameters and corrosion time at initial stage of corrosion were obtained. The results show that the initial corrosion products were mainly composed of ferrihydrite, accompanied with certain amount of α-FeOOH and γ-FeOOH. As the corrosion time increased, the content of γ-FeOOH increased. The corrosion area ratio, mean corrosion depth, maximum corrosion depth and corrosion volume increased exponentially with corrosion time. This may be related to that the corrosion product did not completely cover the metal surface and corrosion extended on the surface and in the depth direction.