The healing effect of polymer films containing a non-chromate inhibitor on iron corrosion at scratched surfaces

A polymer film of 1,2-bis(triethoxysilyl)ethane (C2H5O)(3)Si(CH2)(2)Si(OC2H5)(3) containing sodium octylthiopropionate C8H17S(CH2)(2)COONa (NaOTP) was prepared on an iron surface passivated with 0.1 M Na2MoO4. An inhibitor, NaOTP, probably environmentally acceptable, was markedly effective for corrosion of iron in an aerated 0.1 M NaCl solution. After being covered with the film the surface was crosswise scratched with a knife-edge, the healing ability of the film was examined in the NaCl solution by polarization and impedance measurements. The protective efficiency of the film was extremely high, indicating a prominent healing ability at the scratches on the surface. The him was characterized by FTIR reflection spectroscopy and contact angle measurement. (C) 2000 Elsevier Science Ltd. All rights reserved.