From atomic-scale damage to localized corrosion: Unveiling the lifecycle of inhibitor films under mechanical abrasion

The protective efficacy of corrosion inhibitor films is severely compromised by solid particles in flowing media, significantly increasing the risk of localized corrosion. However, the microscopic damage and self-healing mechanisms of such films remain controversial. Current understanding, largely based on macroscopic weight-loss and electrochemical measurements supplemented by post hoc surface analysis, lacks direct atomic-scale evidence. Here, we combine molecular dynamics simulations with reported experimental evidences to elucidate these mechanisms. We show that the inhibitor film damage originates primarily from mechanical desorption, causing local density reduction. While self-healing occurs via molecular intra-film diffusion and conformational adjustment. Repeated damage leads to permanent defects, which act as channels for solvent penetration to the substrate, initiating localized corrosion. These findings provide key theoretical insights for designing durable, erosion-resistant corrosion inhibitors.