Self-assembled urea-amine compound as vapor phase corrosion inhibitor for mild steel

VPIs (vapor phase corrosion inhibitors) extend their corrosion-inhibiting properties by volatilization and condensation to form a protective film on metal surface. Vapor phase self-assembled films of VPIs have become an attractive means to prevent metal from corrosion. This new methods meet the rust-proof challenges for the steel materials with many advantages. In this paper, bis-(cyclohexylaminomethyl)-urea (BCMU) was developed as VPIs for mild steel. Its corrosion inhibition property was studied by volatile inhibiting sieve test (VIS) and electrochemical measurements. BCMU has good protection effect for mild steel. It suppresses the anodic corrosion reaction and renders the corrosion potential to more positive values. Its interaction with steel surface was investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results suggest that the BCMU interacts with the ferric ions via N and O atoms in its molecule. BCMU inhibits the corrosion processes by blocking the active iron dissolution. It can stabilize the oxide layer and decrease the surface roughness.