Corrosion prevention of passivated iron in 0.1M NaCl by coverage with an ultrathin polymer coating and healing treatment in 0.1M NaNO3

Abstract An ultrathin, ordered and two-dimensional polymer coating was prepared on a passivated iron electrode by modification of 16-hydroxyhexadecanoate ion HO(CH 2 ) 15 CO 2 − self-assembled monolayer with 1,2-bis(triethoxysilyl)ethane (C 2 H 5 O) 3 Si(CH 2 ) 2 Si(OC 2 H 5 ) 3 and octadecyltriethoxysilane C 18 H 37 Si(OC 2 H 5 ) 3 . Subsequently, the electrode was healed in 0.1 M NaNO 3 . Protection of passivated iron against passive film breakdown and corrosion of iron was examined by monitoring of the open-circuit potential and repeated polarization measurements of the polymer-coated and healed electrode in an aerated 0.1 M NaCl solution during immersion for many hours. Localized corrosion was markedly prevented by coverage with the polymer coating and the healing treatment in 0.1 M NaNO 3 . Prominent protection of iron from corrosion in 0.1 M NaCl was observed before the breakdown occurred. The electrode surface covered with the healed passive film and polymer coating was analyzed by contact angle measurement, X-ray photoelectron spectroscopy and electron-probe microanalysis.