Understanding corrosion of active steels in NaCl solution: Experimental and modelling approach

• Investigates corrosion behaviour of active steels in chloride solutions. • Experimental tests reveal time-dependent electrochemical responses. • Surface roughness influences corrosion kinetics and active site formation. • Phase-field model accurately simulates multiscale corrosion dynamics. • Findings aid in improving corrosion resistance in active steel materials. This study investigates the corrosion behaviour of a representative active steel (DC01) in chloride-rich solution through combined experimental and modelling approaches. Potentiostatic and potentiodynamic tests reveal time-dependent corrosion, including a two-step reduction in potential during free immersion and increasing current responses related to the number of active sites. A phase-field corrosion model captures the multiscale dynamics of surface activation, and oxygen transport, accurately reproducing transient current responses and potential shifts observed experimentally. These findings provide deeper insight into active steel corrosion mechanism and how time-dependent electrochemical processes, and oxygen availability govern the corrosion performance.