Superior corrosion resistance of mild steel coated with graphene oxide modified silane coating in chlorinated simulated concrete solution

The corrosion of steel bars is the main reason for the premature failure of reinforced concrete structures, and coating reinforcement is considered to be an effective method to protect steel bar from chloride attack. In this work, we have developed a graphene oxide (GO) modified silane composite coating (isobutyl triethoxysilane combined with tetraethyl orthosilicate) for the corrosion protection of reinforcement bar. The physicochemical characteristics and corrosion resistance performances of mild steel coated with this composite coating was detailed studied by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric, Raman analyses, and electrochemical measurements. The results indicate that the coating with a thickness of about 45 mu m exhibits substantial corrosion resistance effect with a maximum protection efficiency of about 99.36% at chloride media. The superior corrosion protection performance is attributed to the formed covalent bonds between GO and silanol, which strengthens the three-dimensional network structure of the coating. Besides, the uniformly distributed GO immensely slows down the degradation of silane coating structure and improves the stability of the coating, and thus delays the corrosion.