Enhancing Iron Carbonate Properties as a Sustainable Pathway for Mitigating Material Degradation (C2026-00023)

Mingzhe Zheng, Wassim Taleb, Frederick Pessu, Dilshad Shaikhah

Dissolved CO₂ accelerates the internal corrosion of carbon steel pipelines. Although naturally formed iron carbonate (FeCO₃) corrosion products offer some protection, they degrade under physical or chemical disturbance and lack long-term stability. One-time solution intercalation of polymeric nanomaterials during early corrosion forms reinforced nanocomposite FeCO₃ layers with superior localized corrosion resistance and mechanical strength compared to pure FeCO₃ layer. However, the long-term stability of polystyrene microspheres intercalated with FeCO₃ (PS-FeCO₃)layers beyond 48 hours under CO₂ corrosion remains unexplored. A 960-hour in-situ electrochemical test and ex-situ analyses were conducted to evaluate their corrosion resistance, chemical composition, and mechanical integrity. Results showed PS-FeCO₃ layers maintained stable protection with corrosion rates below 0.1 mm/yr after 3 days and lowest-frequency impedance of 10,000 Ω·cm² after 912 hours. Composite layers significantly mitigated pitting corrosion, with the amino-functionalized polystyrene microspheres intercalated FeCO₃ layer exhibiting the best performance—average pit diameter of 71.24 μm, average depth of 26.04 μm, maximum depth of 27.33 μm, and only 42 pits observed. They also demonstrated excellent long-term stability in chemical composition and mechanical integrity. This study offers a green, sustainable alternative to corrosion inhibitors, supporting global carbon neutrality and net-zero goals.