Electrochemical Impedance Spectroscopy of an Al2O3/ Organosilicone/SiO2 Hybrid Coating

Al2O3/organosilicone/SiO2 hybrid sol was prepared by the method of sol-gel with tetra- ethyl orthosilicate (TEOS), methyl triethoxysilane (MTES), diphenyl dimethoxy silane (DDS) and aluminium tri-sec-butoxide as raw materials. Then a hybrid coating was obtained by drying at 100 ℃ for 12 h. The result of Fourier transform infrared spectroscopy (FT-IR) showed that the Al— O—Si bond was formed in the Al2O3/organosilicone/SiO2 hybrid materials. The electrochemical im- pedance spectroscopy (EIS) of the coating immersed in 3.5%NaCl solution for different times was studied. The equivalent circuits were established according to the impedance spectral characteris- tics. The corrosion resistance of the hybrid coating was discussed based on the equivalent circuit and fitted results of electrochemical impedance spectroscopy. The results indicated that the corro- sion resistance of the Al2O3/organosilicone/SiO2hybrid coating was excellent in 3.5%NaCl solution.