The Evolution of the Corrosion Mechanism of Structural Steel Exposed to the Urban Industrial Atmosphere for Seven Years

The corrosion mechanism and characteristics of steel in typical atmospheric environments directly affect the rationality protection methods. This study investigates evolution law Q235 that has been exposed to urban industrial atmosphere for seven years. mass loss is used dynamics analysis. rust layers have characterized by SEM, EDS, XRD. Finally, was analyzed through a combination electrochemical methods, kinetics, layer characteristics. results indicate two-stage power function can still effectively describe rate seven-year exposure complies with law. short-term fail fully reflect performance steel. morphological structures γ-FeOOH α-FeOOH are identified, change from loose flat form granular and, finally, compact into smooth surface. crystalline phases include α-FeOOH, γ-FeOOH, Fe3O4/γ-Fe2O3 α-Fe2O3. Corrosion products initial period mainly followed small amount Fe3O4/γ-Fe2O3. With increase time, increase. SO2 primary factors accelerating corrosion. During first three years corrosion, governed acid cycle reaction mechanism. However, fifth year oxygen-absorbing began gradually dominate, specifically