فهرست نشریات علمی دسترسی آزاد ایران

 A36 steel is a widely used construction material, appreciated for its low carbon content and excellent weldability. However, it is prone to atmospheric corrosion, particularly in humid and polluted areas like Tehran with its high carbon monoxide level. This study examines the corrosion behavior of shot-peened A36 steel in both a 3.5% NaCl solution and the same solution with 9 ppm CO to mimic real-world conditions. Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization were performed on samples immersed for 1, 24, 48, 72, and 96 hours as well as 1 and 2 weeks. The results showed that longer immersion times significantly altered the corrosion mechanisms in the Nyquist plots. Notably, shot peening improved the steel resistance to charge transfer and diffusion. After two weeks in the CO-rich solution, the corrosion current density of shot-peened samples dramatically decreased from 45.7 µA/cm² to 6.5 µA/cm², exhibiting an impressive reduction of 85.5%. Carbon monoxide reacts with water to form carbonic acid which lowered the pH, accelerating the cathodic reactions in more acidic medium. Additionally, shot peening applied compressive stresses on the steel surface that limited corrosive ion penetration. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the formation of iron hydroxide compounds on the surface of shot-peened samples, enhancing their corrosion resistance by restricting the diffusion of corrosive agents.