Corrosion Performance of New-Type Si-Based Weathering Steel in Marine Environment

Among the materials utilized in civil construction, steels have a prominent position as it combines mechanical strength, workability, and low production costs. Thus, weathering steels have been presented as good materials for applications in outdoor environments since they develop a protective oxide layer during their contact with the atmosphere, resulting in excellent corrosion resistance. In order to evaluate the behavior of three weathering steels with different chemical compositions, cyclic corrosion tests were conducted in a simulated marine environment through a dry/wet cycling device for 6, 15, 30, 45 and 50 cycles, each cycle lasting 7 days. After cyclic corrosion tests, the steels were analyzed by electrochemical impedance spectroscopy. Scanning electron microscopy was used to investigate the formed rust, while the crystallographic structure of corrosion products was determined by x-ray diffraction. The presence of alloying elements such as Mo, Cr, Cu, Ni, and Si improved the steel corrosion resistance by forming a more protective rust layer. The weathering steel with the higher Si content presented the best behavior, suggesting that Si influences the corrosion rates.