Preparation and Corrosion Resistance of poly(o-toluidine)/nano SiC/epoxy Composite Coating

In the presence of nano silicon carbide (SiC) particles, using o-toluidine monomer as raw material and ammonium persulfate as the oxidant, the poly(o-toluidine)/nano SiC composite was prepared by in situ polymerization method. Fourier transformation infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were used to characterize the composition and structure of the composite. Poly(o-toluidine) or poly(o- toluidine)/nano SiC composite fillers were mixed with epoxy resin through a solution mixing method and the composite coatings were coated onto the surface of iron coupons. The corrosion resistance of the composite coatings was evaluated by electrochemical measurements in 3.5% NaCl solution as corrosion environment. The results obtained showed that poly(o-toluidine)/nano SiC composite containing coatings has got higher corrosion resistance than that of poly(o-toluidine). The enhancement of corrosion protection efficiency of poly(o-toluidine)/nano SiC composite containing coating is due to the formation of more uniformly passive film on iron surface and the addition of nano SiC particles increase the tortuosity of the diffusion pathway of corrosive substance.