Effects of Adsorption Inhibitors on Fe Corrosion in Aerated Neutral Solutions and the Hard and Soft Acids and Bases Principle

Abstract

An ultrathin （nm in thickness）, two-dimensional polymer protective film was prepared on a passivated Fe surface. A self-assembled mono-molecular layer of 15-hydroxyhexadecanoate ion HO（CH₂）₁₅CO₂^－ was chemisorbed by the stable hard acid and hard base interaction on the Fe surface passivated by anodic polarization in a borate buffer at pH 8.49. The monolayer was modified with 1, 2-bis（triethoxysilyl）ethane （C₂H₅O）₃Si（CH₂）₂Si（OC₂H₅）₃ and hydrolyzed with water. The modified monolayer was then reacted with octadecyltriethoxysilane C₁₈H₃₇Si（OC₂H₅）₃ to form the two-dimensional polymer. Passive film breakdown in the borate buffer with 0.1 M of Cl^－ was markedly protected by coverage with the two-dimensional polymer coating.